The generation _____ makes it difficult for parents to understand their children's opinions.
| A．division | B．gap | C．separation | D．interval |
The split between humans and living apes is thought by some scholars ____ 15 to 20 million years ago.
| A．to occur | B．occurring | C．to have occurred | D．having occurred |
— Linda hasn’t shown up yet.
— It’s strange. She ____.
| A．could | B．might | C．must have | D．should have |
David applied for the position three times ____ he finally got it.
| A．until | B．when | C．before | D．after |
Many questions have been answered by John. He must have previewed the lessons last night, ____ he?
| A．needn’t | B．hasn’t | C．didn’t | D．mustn’t |
Look, ____ fashionable clothes is she wearing that all the eyes are fixed on her!
| A．so | B．such | C．how | D．what |