She was moving out of her old apartment _______ she suddenly realized that the key to the new apartment wasn’t on her.
| A．until | B．once | C．when | D．as if |
21．The moment we heard the news of the earthquake, we began to ________ the work to rescue those who were trapped in the building.
| A．set off | B．set down | C．set aside | D．set about |
Suddenly the idea came to me ____ I might turn to Mr．Smith for help．
| A．what | B．that | C．which | D．whom |
I don' t want to be a person that always cries, but today apparently ____．
| A．I am | B．I will | C．I have | D．I did |
Naturally, after I tell my brother what to do, he ____ go and do the opposite．
| A．will | B．may | C．can | D．must |
Mr．Smith is one of the ____ customers to our restaurant．
| A．ordinary | B．regular | C．normal | D．common |