重点讲解:
1. large numbers of 大量的
The mud is a feeding ground for large numbers of birds.
泥地是大量鸟类找寻食物的地区
。2. under threat 受到...的威胁
His position as leader is under threat.
他的领导职位受到威胁
。3. be unable to do 无法做...
She is unable to conceive.
她不能怀孕
。4. at the same time 同时...
She looked so beautiful, and at the same time so remote.
她看上去如此漂亮,但同时又那么孤傲
。