15．A survey of the opinions of experts ______ that three hours of outdoor exercise a week is good for one’s health.　

　 　A．show　　　 　　　　 B．shows　　　 　　　 C．showed　　 　　　　 D．showing

(C)

14．When he was working there he caught a serious illness from _____ effect he still suffers.　

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

13．No one knows when _______ that boy， but if she does， her parents will be disappointed.

　　 A．she will marry　　　 　　　　　　　　　　　　　 B．she marries　　　

　　 C．will she marry　　 　　　　　　　　　　　　　　 D．does she marry

12．The flowers were so lovely that they __________ in no time.　

　 　　 A．sold　　　　 　　　 B．had been sold　 　 C．were sold　　　 　 D．would sell

11．Mother told Jim to watch the milk until it boiled and then _____ off the gas.　

　　 A．turn　　 　　　　　　 B．turning　　 　　　　 C．turned　　 　　　　　 D．having turned

10．The telephone _______, but by the time I got indoors, it stopped.

　 　　 A．had rung　　　　 　　　　　　　　　　　　　　　 B．was ringing　　　 　

　　　 C．rings　　　 　　　　　　　　　　　　　　　　　　　　 D．has rung

9．-May I go and play with Dick this afternoon, Mum?

-No, you can’t go out _______ your work is being done.

A．before　　　　　　　　 B．until　　　　　　　　　　 C．as　　　　　　　　　　　 D．the moment

8．We must do something to stop factories _____waste water into the river before it is cleaned.．

　　 A．pouring　 　　　　　　 B．to pour 　　　　　　　 C．poured　 　　　　　　 D．being poured

7．-How did you do in the test?

-Not so well. I _____ much better but I misread the directions for Part D．

　　 A．could do 　　　　　　 B．could have done C．must have done 　 D．should do

6．We first met on a train in 2000．We both felt immediately that we ______ each other for years.

A．knew　　　　　　　　　 B．have known　　　　 C．had known　　　　　 D．know