My careless friend Bob received a ticket for speeding．He _________ have driven so fast．

can’t

wouldn’t

mustn’t

shouldn’t

The flu is believed _________ by viruses that like to reproduce in the cells inside the human nose and throat．

causing

being caused

to be caused

to have caused

Seeing her father come back, _________．

tears ran down her cheeks

Her tears ran out

she burst into tears

She burst into crying

The old woman stood still with her eyes _________ the picture．

fixing in

fixing on

fixed in

fixed upon

I can’t remember _________ made the teacher give Mary the permission to leave the class earlier．

that it was what

what it was that

what was it that

that was it what

The thief was brought in, his hands _________ behind his back．

had been tied

tied

being tied

having tied

It’s _________ great fun to talk with you．

a

the

/

an

Scientists say it may be five or six years _________ it is possible to test this medicine on human patients．

since

after

before

when

After many years hard work, the actress’s career really _________．

took on

took off

took up

took out

What a pity! Considering his ability and experience, he _________ better．

need have done

must have done

could have done

might have done