24．He knows little about the city as if he ____there so far.

A．isn't

B．weren't

C．shouldn't have been

D．hadn't been

23．----We didn't see him at the lecture.

----Neither did anyone else. He ____it.

A．may not have attended

B．must have been absent

C．can't have attended

D．couldn't have been present

22．Mary has just left, but I did not know she ____ until yesterday evening.

A．will leave

B．was leaving

C．had left

D．has left

21．____ more clearly , they came up and got close to it.

A．Seeing

B．Seen

C．To see

D．To be seen

20．____ surprised me most was ____they had finished the work so quickly.

A．What; what

B．That; that

C．What; that

D．That; what

19．The school ____ I studied ten years ago is ____ we visited yesterday.

A．where; that

B．that; which

C．where; the one

D．which; that

18．----Why not ask your neighbors for help?

----____ . I hardly know them.

A．I'm afraid not

B．That's a good idea

C．You'd better not

D．That's right

17．----Is she an artist?

----No, she is ____ an artist ____a musician, a famous musician.

A．both; and

B．not; but

C．neither; nor

D．either; or

16．There are many different forms of ____that we can make use of, such as gas, oil winds, waves and so on.

A．energy

B．source

C．force

D．matter

15．Don't play with the burning stick, children. It often ____fire.

A．makes

B．catches

C．sets

D．causes