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 |
1 won’t call you, ________ something unexpected happens.
| A．unless | B．whether | C．because | D．while |
The manager suggested an earlier date ____________ the meeting.
| A．on | B．for | C．about | D．with |
I _____ it as a basic principle of the company that suppliers of raw materials should be given a fair price for their products.
| A．make | B．look | C．take | D．think |
Small sailboats can easily turn over in the water ______ they are not managed carefully.
| A．though | B．before | C．until | D．if |
. Leaves are found on all kinds of trees, but they differ greatly ________ size and shape.
| A．on | B．from | C．by | D．in |