There are eight tips in Dr．Roger's lecture on sleep, and one of them is: to bed early unless you think it is necessary．
| A．doesn't go | B．not to go |
| C．don't go | D．not going |
We saw many students playing on the playground, most of them _____ girls.
| A．are | B．being | C．were | D．have been |
He must have finished his homework for a long time, _____ he?
| A．mustn’t | B．didn’t | C．needn’t | D．hasn’t |
We can see the blue sky and the shining sun. There is no possibility _____ it will rain or snow today.
| A．which | B．where | C．that | D．whether |
Leaders of many countries have been trying to _____ what it is that makes China develop so fast.
| A．carry out | B．figure out | C．break out | D．watch out |
The computer
system _____ suddenly while he was searching for information on the Internet.
A．broke down |
B．broke out | C．broke up | D．broke in |