问题

Most birds find it safe to sleep in the trees,but_______they have eggs or young chicks,they don’t use a nest.

A:why
B:how
C:unless
D:where

正确答案是：

同类题型

Soon after the quakes, one thousand soldiers were sent out to ______ the miners from the local coal mine.[ ]

It was lucky that little Jack was not at home when the fire broke out；otherwise，hehis life．

in the repair shop, he drove his brother’sinstead.

He occupied himself solving the problem.[ ]

I would appreciate it _______ you call back this afternoon for the doctor’s appointment.