1    Nobody knows who will be e              as president or vice president of this country.

2   According to the constitution, it is compulsory for a citizen to ______________(承担) military service.

3  People who can’t ________________(辨别) between colors are said to be color-blind.

4    —Why are you late?

      —I was about to arrive when it o             to me that I had left my bag home, so I had to fetch it.

5    But at last the determination and patience of the scientists ___________  __________(得到好结果，回报) in1996 with a breakthrough—the cloning of Dolly the sheep.

6    I ___________  ___________(开始，着手) researching the habits of snakes to find the easiest way to trap them.

7   I found my bike ___________ ___________ ___________(借助于) a notice in the newspaper.

8   All attempts to rescue the boy with cancer were _____________   _____________(无效果的，无用的)

9   We ___________ __________ ___________(与……合作或一起) a couple from my hotel(Peter and Terri) and hired a car.

10    In many aspects natural clones, such as identical twins, do not ____________(不同，相异) greatly from man-made ones.