Five years ago,Chinese government vowed to bring its energy consumption down by 20%against unit gross domestic product(GDP) during 2006 - 2010,an ambitious but realistic target laid down in a clear-cut term in its 11t...Five years ago,Chinese government vowed to bring its energy consumption down by 20%against unit gross domestic product(GDP) during 2006 - 2010,an ambitious but realistic target laid down in a clear-cut term in its 11th Five-Year Plan for Economic and Social Development.It’s time to finish the goal, but how?展开更多
This paper presents a 16-bit,18-MSPS(million samples per second)flash-assisted successive-approximation-register(SAR)analog-to-digital converter(ADC)utilizing hybrid synchronous and asynchronous(HYSAS)timing control l...This paper presents a 16-bit,18-MSPS(million samples per second)flash-assisted successive-approximation-register(SAR)analog-to-digital converter(ADC)utilizing hybrid synchronous and asynchronous(HYSAS)timing control logic based on an on-chip delay-locked loop(DLL).The HYSAS scheme can provide a longer settling time for the capacitive digital-to-analog converter(CDAC)than the synchronous and asynchronous SAR ADC.Therefore,the issue of incomplete settling or ringing in the DAC voltage for cases of either on-chip or off-chip reference voltage can be solved to a large extent.In addition,the fore-ground calibration of the CDAC’s mismatch is performed with a finite-impulse-response bandpass filter(FIR-BPF)based least-mean-square(LMS)algorithm in an off-chip FPGA(field programmable gate array).Fabricated in 40-nm CMOS process,the proto-type ADC achieves 94.02-dB spurious-free dynamic range(SFDR),and 75.98-dB signal-to-noise-and-distortion ratio(SNDR)for a 2.88-MHz input under 18-MSPS sampling rate.展开更多
What makes an ideal life?For many,it’s escaping crowded and expensive big cities and the accompanying long,exhausting commutes to settle in a beautiful,warm,and budget-friendly city,or hitting the road and going else...What makes an ideal life?For many,it’s escaping crowded and expensive big cities and the accompanying long,exhausting commutes to settle in a beautiful,warm,and budget-friendly city,or hitting the road and going elsewhere anytime you want.No alarm clocks,no punching in for work,no pressure from bosses-do a little work and then enjoy your life.This is the life for many digital nomads.展开更多
The transformation of Yundang Lake from a stinky lake to an urban reception hall has made it a showcase of ecologival restoration in China.BEFORE settling down in the City of Xiamen,Scott Patrick and his wife spent lo...The transformation of Yundang Lake from a stinky lake to an urban reception hall has made it a showcase of ecologival restoration in China.BEFORE settling down in the City of Xiamen,Scott Patrick and his wife spent long hours searching online for just the right part of the city.When they saw Yundang Lake in west Xiamen,the couple knew they had hit the jackpot.“The picture of the beautiful lake circled by lush vegetation caught our attention.We knew this was the place we were looking for,”said Patrick.Later,after setting foot in Xiamen,he told himself he had definitely made the right life decision.展开更多
Before settling down in the city of Xiamen,Scott Patrick and his wife spent long hours searching online for just the right part of the city.When they saw Yundang Lake in west Xiamen,the couple knew they had hit the ja...Before settling down in the city of Xiamen,Scott Patrick and his wife spent long hours searching online for just the right part of the city.When they saw Yundang Lake in west Xiamen,the couple knew they had hit the jackpot.“The picture of the beautiful lake circled by lush vegetation caught our attention.We knew this was the place we were looking for,”said Patrick.Later,after setting foot in Xiamen,he told himself he had definitely made the right life decision.展开更多
Quilt Arts of South Africa Edited by MARSHA MACDOWELL Indiana University Press In the far south of the African continent,women have a long tradition of crafting bed coverings using textile techniques commonly used in ...Quilt Arts of South Africa Edited by MARSHA MACDOWELL Indiana University Press In the far south of the African continent,women have a long tradition of crafting bed coverings using textile techniques commonly used in quilting,a practice deeply embedded in the histories of the San and Khoi peoples.Between the late 1600s and the early 1800s,South Africa experienced an influx of Dutch,French,Indian,and British settlers,including military personnel,traders,miners,and missionaries.These groups introduced their own cultural traditions,including the art of quilt making.Today,quilting thrives as a vibrant art form in South Africa.展开更多
By increasing particle concentration and G value (root-mean-square velocity gradient) to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneousl...By increasing particle concentration and G value (root-mean-square velocity gradient) to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneously improve operational stabilization. Due to the gradual decrease in upward flow-rate of raw water, a floes blanket would form and suspend in the middle section of the settler, not at the bottom as in a conventional clarifier. Enough large floes, resulted from flocculation or fltration, would continuously settle out of the floes blanket, and simultaneously, the floes in raw water or those forming above the blanket would ceaselessly enter the floes blanket. As a result, the floes concentration in the blanket could keep a dynamic balance. The hydrodynamic shear in the blanket was improved by flow separation, which was induced by the abrupt change in flow channel. Due to the floes blanket and improved hydrodynamic shear, flocculation would be enhanced, which was helpful for removing fine particles in raw water. A comparative study showed that the novel vertical-flow settler had a much better performance in the removal of the particles in raw water than a conventional one, when they treated kaolin suspensions of different concentrations (500, 100 and 50 mg/L, respectively) coagulated by polyaluminum chloride(PAC1) at the up-flow rates of 1 and 2 mm/s, respectively.展开更多
Criterion of differential settlement in subgrade is useful for keeping road in a good serving condition. The theory of traditional materials strength and their technologic economy are applied to analyze the additional...Criterion of differential settlement in subgrade is useful for keeping road in a good serving condition. The theory of traditional materials strength and their technologic economy are applied to analyze the additional bend stress of the pavement structure, the equivalent beam of elastic foundation and influence on the pavement structure of an uneven settlement. The allowable settling ratio of pavement index ( △i ) is got and is used to appraise the uneven settlement standard value in subgrade. The allowable settling ratio of pavement index is applied in an certain widening expressway project and △i ≤0.36 % is attained by the analyzing, calculating and adding a certain safe coefficient. This value was put into practice and is effective during the past two years.展开更多
A method of measuring the vortex beam topological charge(TC)is proposed based on a device that can directly extract the plane wave form from the vortex beam in which the different propagation angles of the plane waves...A method of measuring the vortex beam topological charge(TC)is proposed based on a device that can directly extract the plane wave form from the vortex beam in which the different propagation angles of the plane waves are uniquely related to the different TCs.Then the TC can be obtained by simply comparing the energy values perceived by two fixed sensors in the detection location with the help of twin omnidirectional energy absorbers(OEAs).Because the settled detection relies only on the simple quantitative value at two fixed positions,neither pattern recognition nor field analysis procedure is applied,thus allowing faster measurement.Some features of the methodology are investigated,and the numerical simulations verify the feasibility and robustness of the system.展开更多
Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai.China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fu...Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai.China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fungi.They were also examined for atlatoxin endotoxin, and potential to stimulate production of human interleukin 1β (IL-1β) and to consume complement.The concentrations of total microorganisms were consistently greater than 10~7 CFU/g and ranged from 10~7 to 10~9 CFU/g.In general, the level of microbial contamination was greater in the hay dust samples than in the rice dust samples, with bacteria being the most numerous microorganisms observed followed by molds, thermophilic actinomycetes, and yeasts.The predominant fungi were species of Aspergillus, Cladosporium, Penicillium.Trichosporon, and Cryplococcus.No significant levels of aflatoxin were observed and the isolates of A.flavus examined lack significant aflatoxigenic potential.The levels of microorganisms in these samples, the types of organisms found, and the inflammatory mediators such as endotoxin suggest that workers exposed to these dusts may be at risk for respiratory illness. 1990 Academic Press.Inc.展开更多
The SWAT model was used to predict total phosphorus (TP) loadings for a 1555-ha karst watershed—Chapel Branch Creek (CBC)—which drains to a lake via a reservoir-like embayment (R-E). The model was first tested for m...The SWAT model was used to predict total phosphorus (TP) loadings for a 1555-ha karst watershed—Chapel Branch Creek (CBC)—which drains to a lake via a reservoir-like embayment (R-E). The model was first tested for monthly streamflow predictions from tributaries draining three potential source areas as well as the downstream R-E, followed by TP loadings using data collected March 2007-October 2009. Source areas included 1) a golf course that received applied wastewater, 2) urban areas, highway, and some agricultural lands, and 3) a cave spring draining a second golf course along with agricultural and forested areas, including a substantial contribution of subsurface water via karst connectivity. SWAT predictions of mean monthly TP loadings at the first two source outlets were deemed reasonable. However, the predictions at the cave spring outlet were somewhat poorer, likely due to diffuse variable groundwater flow from an unknown drainage area larger than the actual surface watershed, for which monthly subsurface flow was represented as a point source during simulations. Further testing of the SWAT model to predict monthly TP loadings at the R-E, modeled as a completely mixed system, resulted in their over-predictions most of the months, except when high lake water levels occurred. The mean monthly and annual flows were calibrated to acceptable limits with the exception of flow over-prediction when lake levels were low and surface water from tributaries disappeared into karst connections. The discrepancy in TP load predictions was attributed primarily to the use of limited monthly TP data collected during baseflow in the embayment. However, for the 22-month period, over-prediction of mean monthly TP load (34.6 kg/mo) by 13% compared to measured load (30.6 kg/mo) in the embayment was deemed acceptable. Simulated results showed a 42% reduction in TP load due to settling in the embayment.展开更多
Asthma and allergies are considered by many physicians as being triggered by different substances in the air that people breathe. The lung is the most common site of injury by airborne pollutants. Acute effects, howev...Asthma and allergies are considered by many physicians as being triggered by different substances in the air that people breathe. The lung is the most common site of injury by airborne pollutants. Acute effects, however, may also include non-respiratory signs and symptoms, which may depend upon toxicological characteristics of the substances and host-related factors. The studying of indoor air quality can provide a method for appropriate remedial action. Research suggests that SHD (Settled House Dust) may be a significant source for indoor exposure to different substances. This research study consisted of sampling dust from homes in different area codes. The dust samples were collected from August 2006 thru March 2007 and analyzed using GC/MS (Gas Chromatography/Mass Spectrometry). The purpose of this research study will display how sampling household dust is a powerful tool for identifying chemicals that contribute to poor indoor air quality.展开更多
The new national technical standards innovation base has officially settled in Guangzhou.The inauguration ceremony and a themed seminar were celebrated on December11,2015.Addressing the meeting,SAC Vice-Administrator ...The new national technical standards innovation base has officially settled in Guangzhou.The inauguration ceremony and a themed seminar were celebrated on December11,2015.Addressing the meeting,SAC Vice-Administrator Yu Xinli said that,the innovation base as an attempt to promote the innovative development of standardization is of great significance to deepen the reform and create favorable environment for standardization development.展开更多
Indoor settled harmattan dusts at seven sampling stations from the University of Agriculture Makurdi were collected between November, 2014 to March, 2015 (five months) using the wipe sampling methodology. Gravimetric ...Indoor settled harmattan dusts at seven sampling stations from the University of Agriculture Makurdi were collected between November, 2014 to March, 2015 (five months) using the wipe sampling methodology. Gravimetric measurement of the dust samples from all the sample locations revealed that dust loading within the institution during the period of assessment ranges from 4.475 - 6.533 g/m2. Masses of indoor settled dust were expectedly higher along high traffic, untarred roads and construction sites as well as in older buildings than others during the period of this study. AAS analysis of the dust samples shows that heavy metal concentrations (mg/kg dry weight) throughout the sampling stations during the period of investigation range from 0.2372 - 0.7152 for Cu, 293.6 - 884.9 for Fe, 4.265 - 68.55 for Mn and 4.239 - 42.53 for Zn. The concentrations of all the metals investigated were found to be lower when compared with related values in literature and were within acceptable limits during the period of this study. Pearson correlation matrix also shows positive correlation between the possible metal pairs at 95% level of confidence, indicating a similar source which may be from anthropogenic activities within and outside the area.展开更多
In spring this year,the writershad an interview at JiangsuSuntory Ltd,a Sino-Japanesejoint venture modern foodstuffenterprise founded 11 yearsago with a joint investment ofUS$25 million,producingmainly Prince Brand b...In spring this year,the writershad an interview at JiangsuSuntory Ltd,a Sino-Japanesejoint venture modern foodstuffenterprise founded 11 yearsago with a joint investment ofUS$25 million,producingmainly Prince Brand beer andmalt as well as other serialproducts.展开更多
China,the big factory offering various commodities to companies and individuals all over the world,is attracting more and more merchants purchasing goods in various ways,through agents,on site,via modern communication...China,the big factory offering various commodities to companies and individuals all over the world,is attracting more and more merchants purchasing goods in various ways,through agents,on site,via modern communication,etc.One essential concern of these merchants is the quality of these commodities.How can the commodity quality be ensured?If there are展开更多
《大学英语》精读课本(李荫华主编)第四册第一单元的课文中,有这样一句话:By the time I arrived home,the boys had al-ready settled their accounts:$150 in labor costs,$40 for gaso-line,and a like amount for giftsboxes of can...《大学英语》精读课本(李荫华主编)第四册第一单元的课文中,有这样一句话:By the time I arrived home,the boys had al-ready settled their accounts:$150 in labor costs,$40 for gaso-line,and a like amount for giftsboxes of candy for saintly neighborswho had VoIunteered starion wagons and help in delivery and展开更多
文摘Five years ago,Chinese government vowed to bring its energy consumption down by 20%against unit gross domestic product(GDP) during 2006 - 2010,an ambitious but realistic target laid down in a clear-cut term in its 11th Five-Year Plan for Economic and Social Development.It’s time to finish the goal, but how?
基金supported by Qingdao Hi-image Technologies Co., Ltdin part by the NSFC of China under Grant 62174149, 61974118, 62004156the National Key R&D Program of China under Grant 2022YFC2404902
文摘This paper presents a 16-bit,18-MSPS(million samples per second)flash-assisted successive-approximation-register(SAR)analog-to-digital converter(ADC)utilizing hybrid synchronous and asynchronous(HYSAS)timing control logic based on an on-chip delay-locked loop(DLL).The HYSAS scheme can provide a longer settling time for the capacitive digital-to-analog converter(CDAC)than the synchronous and asynchronous SAR ADC.Therefore,the issue of incomplete settling or ringing in the DAC voltage for cases of either on-chip or off-chip reference voltage can be solved to a large extent.In addition,the fore-ground calibration of the CDAC’s mismatch is performed with a finite-impulse-response bandpass filter(FIR-BPF)based least-mean-square(LMS)algorithm in an off-chip FPGA(field programmable gate array).Fabricated in 40-nm CMOS process,the proto-type ADC achieves 94.02-dB spurious-free dynamic range(SFDR),and 75.98-dB signal-to-noise-and-distortion ratio(SNDR)for a 2.88-MHz input under 18-MSPS sampling rate.
文摘What makes an ideal life?For many,it’s escaping crowded and expensive big cities and the accompanying long,exhausting commutes to settle in a beautiful,warm,and budget-friendly city,or hitting the road and going elsewhere anytime you want.No alarm clocks,no punching in for work,no pressure from bosses-do a little work and then enjoy your life.This is the life for many digital nomads.
文摘The transformation of Yundang Lake from a stinky lake to an urban reception hall has made it a showcase of ecologival restoration in China.BEFORE settling down in the City of Xiamen,Scott Patrick and his wife spent long hours searching online for just the right part of the city.When they saw Yundang Lake in west Xiamen,the couple knew they had hit the jackpot.“The picture of the beautiful lake circled by lush vegetation caught our attention.We knew this was the place we were looking for,”said Patrick.Later,after setting foot in Xiamen,he told himself he had definitely made the right life decision.
文摘Before settling down in the city of Xiamen,Scott Patrick and his wife spent long hours searching online for just the right part of the city.When they saw Yundang Lake in west Xiamen,the couple knew they had hit the jackpot.“The picture of the beautiful lake circled by lush vegetation caught our attention.We knew this was the place we were looking for,”said Patrick.Later,after setting foot in Xiamen,he told himself he had definitely made the right life decision.
文摘Quilt Arts of South Africa Edited by MARSHA MACDOWELL Indiana University Press In the far south of the African continent,women have a long tradition of crafting bed coverings using textile techniques commonly used in quilting,a practice deeply embedded in the histories of the San and Khoi peoples.Between the late 1600s and the early 1800s,South Africa experienced an influx of Dutch,French,Indian,and British settlers,including military personnel,traders,miners,and missionaries.These groups introduced their own cultural traditions,including the art of quilt making.Today,quilting thrives as a vibrant art form in South Africa.
基金The Hi-Tech Research and Development Program (863) of China (No. 2002AA601290 2003AA601010-03) and the NationalNatural Science Foundation of China (No. 50178067)
文摘By increasing particle concentration and G value (root-mean-square velocity gradient) to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneously improve operational stabilization. Due to the gradual decrease in upward flow-rate of raw water, a floes blanket would form and suspend in the middle section of the settler, not at the bottom as in a conventional clarifier. Enough large floes, resulted from flocculation or fltration, would continuously settle out of the floes blanket, and simultaneously, the floes in raw water or those forming above the blanket would ceaselessly enter the floes blanket. As a result, the floes concentration in the blanket could keep a dynamic balance. The hydrodynamic shear in the blanket was improved by flow separation, which was induced by the abrupt change in flow channel. Due to the floes blanket and improved hydrodynamic shear, flocculation would be enhanced, which was helpful for removing fine particles in raw water. A comparative study showed that the novel vertical-flow settler had a much better performance in the removal of the particles in raw water than a conventional one, when they treated kaolin suspensions of different concentrations (500, 100 and 50 mg/L, respectively) coagulated by polyaluminum chloride(PAC1) at the up-flow rates of 1 and 2 mm/s, respectively.
基金Sponsored by Project of Ning Xia Hui Autonormous Region Communications Department2005
文摘Criterion of differential settlement in subgrade is useful for keeping road in a good serving condition. The theory of traditional materials strength and their technologic economy are applied to analyze the additional bend stress of the pavement structure, the equivalent beam of elastic foundation and influence on the pavement structure of an uneven settlement. The allowable settling ratio of pavement index ( △i ) is got and is used to appraise the uneven settlement standard value in subgrade. The allowable settling ratio of pavement index is applied in an certain widening expressway project and △i ≤0.36 % is attained by the analyzing, calculating and adding a certain safe coefficient. This value was put into practice and is effective during the past two years.
基金supported by the National Natural Science Foundation of China(Grant Nos.61975015,61575022,and 61421001)the Beijing Natural Science Foundation,China(Grant No.L191004).
文摘A method of measuring the vortex beam topological charge(TC)is proposed based on a device that can directly extract the plane wave form from the vortex beam in which the different propagation angles of the plane waves are uniquely related to the different TCs.Then the TC can be obtained by simply comparing the energy values perceived by two fixed sensors in the detection location with the help of twin omnidirectional energy absorbers(OEAs).Because the settled detection relies only on the simple quantitative value at two fixed positions,neither pattern recognition nor field analysis procedure is applied,thus allowing faster measurement.Some features of the methodology are investigated,and the numerical simulations verify the feasibility and robustness of the system.
文摘Fourteen samples of settled dust from two factories processing rice and wheat straw near Shanghai.China, were examined by dilution plating for total bacteria, gram-negative bacteria, thermophilic actinomycetes, and fungi.They were also examined for atlatoxin endotoxin, and potential to stimulate production of human interleukin 1β (IL-1β) and to consume complement.The concentrations of total microorganisms were consistently greater than 10~7 CFU/g and ranged from 10~7 to 10~9 CFU/g.In general, the level of microbial contamination was greater in the hay dust samples than in the rice dust samples, with bacteria being the most numerous microorganisms observed followed by molds, thermophilic actinomycetes, and yeasts.The predominant fungi were species of Aspergillus, Cladosporium, Penicillium.Trichosporon, and Cryplococcus.No significant levels of aflatoxin were observed and the isolates of A.flavus examined lack significant aflatoxigenic potential.The levels of microorganisms in these samples, the types of organisms found, and the inflammatory mediators such as endotoxin suggest that workers exposed to these dusts may be at risk for respiratory illness. 1990 Academic Press.Inc.
文摘The SWAT model was used to predict total phosphorus (TP) loadings for a 1555-ha karst watershed—Chapel Branch Creek (CBC)—which drains to a lake via a reservoir-like embayment (R-E). The model was first tested for monthly streamflow predictions from tributaries draining three potential source areas as well as the downstream R-E, followed by TP loadings using data collected March 2007-October 2009. Source areas included 1) a golf course that received applied wastewater, 2) urban areas, highway, and some agricultural lands, and 3) a cave spring draining a second golf course along with agricultural and forested areas, including a substantial contribution of subsurface water via karst connectivity. SWAT predictions of mean monthly TP loadings at the first two source outlets were deemed reasonable. However, the predictions at the cave spring outlet were somewhat poorer, likely due to diffuse variable groundwater flow from an unknown drainage area larger than the actual surface watershed, for which monthly subsurface flow was represented as a point source during simulations. Further testing of the SWAT model to predict monthly TP loadings at the R-E, modeled as a completely mixed system, resulted in their over-predictions most of the months, except when high lake water levels occurred. The mean monthly and annual flows were calibrated to acceptable limits with the exception of flow over-prediction when lake levels were low and surface water from tributaries disappeared into karst connections. The discrepancy in TP load predictions was attributed primarily to the use of limited monthly TP data collected during baseflow in the embayment. However, for the 22-month period, over-prediction of mean monthly TP load (34.6 kg/mo) by 13% compared to measured load (30.6 kg/mo) in the embayment was deemed acceptable. Simulated results showed a 42% reduction in TP load due to settling in the embayment.
文摘Asthma and allergies are considered by many physicians as being triggered by different substances in the air that people breathe. The lung is the most common site of injury by airborne pollutants. Acute effects, however, may also include non-respiratory signs and symptoms, which may depend upon toxicological characteristics of the substances and host-related factors. The studying of indoor air quality can provide a method for appropriate remedial action. Research suggests that SHD (Settled House Dust) may be a significant source for indoor exposure to different substances. This research study consisted of sampling dust from homes in different area codes. The dust samples were collected from August 2006 thru March 2007 and analyzed using GC/MS (Gas Chromatography/Mass Spectrometry). The purpose of this research study will display how sampling household dust is a powerful tool for identifying chemicals that contribute to poor indoor air quality.
文摘The new national technical standards innovation base has officially settled in Guangzhou.The inauguration ceremony and a themed seminar were celebrated on December11,2015.Addressing the meeting,SAC Vice-Administrator Yu Xinli said that,the innovation base as an attempt to promote the innovative development of standardization is of great significance to deepen the reform and create favorable environment for standardization development.
文摘Indoor settled harmattan dusts at seven sampling stations from the University of Agriculture Makurdi were collected between November, 2014 to March, 2015 (five months) using the wipe sampling methodology. Gravimetric measurement of the dust samples from all the sample locations revealed that dust loading within the institution during the period of assessment ranges from 4.475 - 6.533 g/m2. Masses of indoor settled dust were expectedly higher along high traffic, untarred roads and construction sites as well as in older buildings than others during the period of this study. AAS analysis of the dust samples shows that heavy metal concentrations (mg/kg dry weight) throughout the sampling stations during the period of investigation range from 0.2372 - 0.7152 for Cu, 293.6 - 884.9 for Fe, 4.265 - 68.55 for Mn and 4.239 - 42.53 for Zn. The concentrations of all the metals investigated were found to be lower when compared with related values in literature and were within acceptable limits during the period of this study. Pearson correlation matrix also shows positive correlation between the possible metal pairs at 95% level of confidence, indicating a similar source which may be from anthropogenic activities within and outside the area.
文摘In spring this year,the writershad an interview at JiangsuSuntory Ltd,a Sino-Japanesejoint venture modern foodstuffenterprise founded 11 yearsago with a joint investment ofUS$25 million,producingmainly Prince Brand beer andmalt as well as other serialproducts.
文摘China,the big factory offering various commodities to companies and individuals all over the world,is attracting more and more merchants purchasing goods in various ways,through agents,on site,via modern communication,etc.One essential concern of these merchants is the quality of these commodities.How can the commodity quality be ensured?If there are
文摘《大学英语》精读课本(李荫华主编)第四册第一单元的课文中,有这样一句话:By the time I arrived home,the boys had al-ready settled their accounts:$150 in labor costs,$40 for gaso-line,and a like amount for giftsboxes of candy for saintly neighborswho had VoIunteered starion wagons and help in delivery and