当你在野外发生意外,急需援救时,你应该打出什么信号?A.SOS B. UFO C.WTO
When the teacher came in, all of us _______.
It ______ that he has been ill for a long time.
I spent half an hour ___________ my homework.
My father gave up ________ at last.
I haven’t seen the movie and my brother hasn’t _______.