Though it's still unclear why the original domestication happened, Science News' Freda Kreier reports that the event coincided with the Sahara growing larger and drier.
尽管尚不清楚最初的驯化为何发生，但《科学新闻》的弗雷达·克雷尔报道说，这一事件与撒哈拉沙漠变得更大更干燥的时间相吻合。
Prehistoric humans may have enlisted donkeys' help in navigating the expanding Sahara.
史前人类可能利用驴的帮助来应对不断扩大的撒哈拉沙漠。
calls for evidence from the Sahara.
呼吁提供撒哈拉的证据。
例句取自历年考研英语真题，翻译为机器生成，仅供学习参考。