摘要
在非洲南部的纳米布沙漠,雨季时地上会出现很多圆圈,圈外长草,圈内不长草。科学家一直在研究这些圆圈是怎么形成的。
For over 50 years,ecologists have studied and debated the mystery of the Namib Desert's“fairy circles”.These cir⁃cular patches(小块土地),mostly barren(不长草的)of grasses,have spread across 1,100 kilometers in the arid grasslands of Southern Africa.
