The governments are very cautious about setting a new policy and make no decision _____ they are quite sure it is the right one．
| A．because | B．when | C．until | D．as |
12. Mr Black has two sons, ________ are fond of collecting stamps.
| A．all of whom | B．all of them | C．both of them | D．both of whom |
11. “Do you prefer ________ rather than ________ by bus?” asked my mother.
| A．walking there; going | B．to alk to there; go |
| C．to walk there; go | D．walking to there; going |
10. My brother was born on January, 10th, 1990 ________ it was snowing heavily.
| A．which | B．when | C．in which | D．That |
9. “Do you have any questions ________ clear to you?” the teacher asked.
| A．which are not | B．that isn’t | C．not to | D．To |
8. “Please make ________ at home,” the landlady said to the children.
| A．yourself | B．you | C．yourselves | D．Themselves |