2 . The clever boy made a hole in the wall, ________ which he could see what was happening inside the house. (U1非限制性定语从句练习25题) (用适当的词填空)

3 . ________a lower temperature to draw out the extract, Tu Youyou found a substance________worked.

A．Using; that

B．Used; which

C．To use; what

D．Use;who

4 . The old man has a son and two daughters, ________treat him well, ________made him very sad.

A．none of them; that	B．none of them; which
C．none of whom; that	D．none of whom; which

5 . ________worries most people is that these fertilisers may cause pollution. (用适当的词填空)

6 . ________ (instant) you turn it on, you’ll get boiling water from the hot tap.

8 . Your lights will come on________you enter the door along with your favorite music or TV programs.

A．the instant

B．as soon as

C．immediately

D．All the above

9 . ________is often the case with human beings, many animals sleep a lot when young, but sleep much less when they get older.

A．Which

B．It

C．As

D．What

10 . This produced a chain reaction, ________made________possible for life to develop.

A．what; that

B．what; it

C．which; that

D．which; it