Can you see the boys _____ football on the playground? They are my classmates.
| A．to play | B．playing | C．plays | D．Played |
-I’m afraid the meeting has begun. -Don’t worry. It ___ until the bell ____.
| A．doesn’t begin ;rings | B．won’t begin ; will ring |
| C．won’t begin ;rings | D．doesn’t begin ;will ring |
In summer milk will quickly go bad _____it is put into a fridge.
| A．though | B．unless | C．because | D．once |
I have heard a lot of good things about you _____ I came back from abroad.
| A．since | B．when | C．before | D． until |
—Why didn't you try your best to get on the bus?
—I tried to, but it had started moving ________ I could get on it.
| A．before | B．after | C．since | D．if |
—Did you call Jim back?
—I don't need to, ________ we'll have a meeting together tonight.
| A．though | B．unless | C．because | D．if |