You ______ be hungry already — you had lunch only two hours ago!
| A．wouldn’t | B．can’t | C．mustn’t | D．needn’t |
She set off at 9 a.m. and ____ the airport an hour later.
| A．will reach | B．would reach |
| C．had reached | D．reached |
If ____ in, viruses can result in illness or even death.
| A．breathe | B．breathing |
| C．breathed | D．to breathe |
By the 1920s, Howard Carter ____ an explorer.
| A．has become | B．had become |
| C．became | D．would become |
Three mountains, Meili, Baimang and Haba, _____ are covered with snow, tower over the land.
| A．that | B．what |
| C．which | D．as |
Is _______ three hours _______ the poor boy to come to school on foot?
| A．it; that it takes | B．there; that it takes |
| C．there; when | D．it; that |