English is widely taught as an FL （foreign language） in most middle schools in China. Chinese students have improved their English reading and writing these years, but they are relatively poor in listening and speak...English is widely taught as an FL （foreign language） in most middle schools in China. Chinese students have improved their English reading and writing these years, but they are relatively poor in listening and speaking. The author, based on the empirical study, made an investigation on Senior Three students in Leshan city. The statistics from the questionnaire indicate the problem of ＂Mute-crux＂ in English teaching and learning. This paper explores the reasons that cause the problem： teachers＇ use of the traditional ways, just emphasizing the transmission of English knowledge, but ignoring the meaningful communication with students; exercise-based and exam-oriented teaching, which cause students＇ rote-learning. The author proposes that Chinese English teachers ought to change the traditional notions and adopt effective ways to encourage students to speak bravely in order to improve their speaking abilities展开更多
The oxygen isotope composition of minerals from quartz veins and host eclogites in the Dabie terrane was measured in order to place geochemical constraints on the origin and transport of metamorphic fluid. The results...The oxygen isotope composition of minerals from quartz veins and host eclogites in the Dabie terrane was measured in order to place geochemical constraints on the origin and transport of metamorphic fluid. The results are discussed together with structural and petrological relationships between quartz vein and wallrock. The quartz veins can be temporally classified into three groups: (1) synmetamorphic vein which would be formed prior to eclogite-facies recrystallization when they were exhumated from mantle depths to deep crustal levels; (2) early retrogressive vein which was formed in the early stage of eclogite exhumation subsequent to the recrystallization, the vein-forming fluid is still relevant to the eclogites; (3) late retrogressive vein which was formed in the late stage of eclogite exhumation from deep crustal to upper crustal levels, oxygen isotope fractionation between vein quartz and host eclogite significantly deviates from equilibrium values and the vein-forming fluid was principally derived from granitic gneiss hosting the eclogites. For the synmetamorphic vein, it appears that local advective transport of fluid is the predominant mechanism in the processes of vein precipitation; the scale of oxygen isotope homogenization within the veins is much larger than that within the associated eclogites. The vein-forming fluid would be derived from the exsolution of dissolved hydroxyls within eclogite minerals due to significant pressure decrease. Fluid flow prior to the eclogite-facies recrystallization and the early retrogression may occur mainly along pressure gradients.展开更多
文摘English is widely taught as an FL （foreign language） in most middle schools in China. Chinese students have improved their English reading and writing these years, but they are relatively poor in listening and speaking. The author, based on the empirical study, made an investigation on Senior Three students in Leshan city. The statistics from the questionnaire indicate the problem of ＂Mute-crux＂ in English teaching and learning. This paper explores the reasons that cause the problem： teachers＇ use of the traditional ways, just emphasizing the transmission of English knowledge, but ignoring the meaningful communication with students; exercise-based and exam-oriented teaching, which cause students＇ rote-learning. The author proposes that Chinese English teachers ought to change the traditional notions and adopt effective ways to encourage students to speak bravely in order to improve their speaking abilities
基金the Ministry of Science and Technology of China (Grant No. G1999075503) and the Chinese Academy of Sciences (Grant No. KZCX2-107).
文摘The oxygen isotope composition of minerals from quartz veins and host eclogites in the Dabie terrane was measured in order to place geochemical constraints on the origin and transport of metamorphic fluid. The results are discussed together with structural and petrological relationships between quartz vein and wallrock. The quartz veins can be temporally classified into three groups: (1) synmetamorphic vein which would be formed prior to eclogite-facies recrystallization when they were exhumated from mantle depths to deep crustal levels; (2) early retrogressive vein which was formed in the early stage of eclogite exhumation subsequent to the recrystallization, the vein-forming fluid is still relevant to the eclogites; (3) late retrogressive vein which was formed in the late stage of eclogite exhumation from deep crustal to upper crustal levels, oxygen isotope fractionation between vein quartz and host eclogite significantly deviates from equilibrium values and the vein-forming fluid was principally derived from granitic gneiss hosting the eclogites. For the synmetamorphic vein, it appears that local advective transport of fluid is the predominant mechanism in the processes of vein precipitation; the scale of oxygen isotope homogenization within the veins is much larger than that within the associated eclogites. The vein-forming fluid would be derived from the exsolution of dissolved hydroxyls within eclogite minerals due to significant pressure decrease. Fluid flow prior to the eclogite-facies recrystallization and the early retrogression may occur mainly along pressure gradients.
