We asked John and Jerry, but ________ of them could offer a satisfactory explanation．

either

none

both

neither

It is almost five years ________ we saw each other last time．

before

since

after

when

After a fire broke out in the lab，a lot of equipment ________．

is damaged

had damaged

damaged

was damaged

I’m going to the supermarket this afternoon．Do you have anything ________?

to be buying

to buy

for buying

bought

We hope that as many people as possible ________ join us for the picnic tomorrow．

need

must

should

can

We ________ have proved great adventures, but we have done the greatest march ever made in the past ten years．

needn’t

may not

shouldn’t

mustn’t

It ________ be him．It’s his turn tomorrow．

mustn’t

won’t

can’t

needn’t

There’s no light on－they ________ be at home．

can’t

mustn’t

needn’t

shouldn’t

Some aspects of a pilot’s job be boring, and ________ pilots ________ often work at inconvenient hours．

can; have to

may; can

have to; may

ought to; must

He _________ another career, but at the time，he didn’t have enough money to attend graduate school．

might choose

might have chosen

had to choose

must have chosen