18．We can never forget the days ________ the two astronauts in spaceship worked together and the days ________ we spent together.

A．when；which　 　　B．which；when　　 C．what；that　 　D．on which；when

17. -Will you go to the party?

-Of course I will ________.

A．if invited　　　　　　　　　　　　　　　　　　　　　　　　　 B．if having invited　　　

C．if I was invited　　　　　　　　　　　　　　　　　　　　　 D．if I will be invited

16．-I told you that he would come to see you.

-Actually I had little doubt ________ it was true.

A．whether　 　　　　　　　　　　 B．that　　　　　　　　　　　　 C．since 　　　　　　　 D．if

15. All substances, ________ solid, liquids or gases, are made up of entirely atoms.

A．whether they　　 　　　 　　　　　　　　　　 B．whether　　　　　　　　

C．whether are they　　　 　　　　　　　　　　 D．whether are

14．I suggest that we should take part in more such activities in the future ________ we did yesterday.

A．which　　　　　　　 　　B．as　　　　　　　　　　　　　 C．that 　　　　　　　 D．than

13．You may depend ________ it won’t happen again.

A．that　 　　　　　　　　　　 B．on that　　　　　　　　　　 C．on it that 　　D．on it

12．It will be five years ________ we meet again.

A．since　 　　　　　　 　　B．after　　　　　　　　　　　 C．before　 　 　　D．when

11．________ China’s reform and opening up in late 1978, its quick development has aroused worldwide attention, which has made America anxious about it.

A．When　 　　　　　 　　B．As　　　　　　　　　　　　　 C．While 　　 　　D．Since

10．The river，________ the banks are covered with trees, is very long.

A．whose　 　　　　　 　　B．which　　　　　　　　　　 C．of which 　　D．which of

9．It is thought that one billion people in the world, ________ is ，half the world’s workers, earn their living by farming.

A．if 　　　　　　　　　 　　B．that　　　　　　　　　　　　 C．which 　　 　　D．what