单项选择题
A. needn't B. shouldn't C. can't D. mustn't
（）with the size of the whole earth, the highest mountai...
单项选择题（）with the size of the whole earth, the highest mountain does not seem high at all.
A. When compared B. When comparing C. Compare D. Comparing
What Marx（）by a particular society was an organization ...
单项选择题What Marx（）by a particular society was an organization of people making a living together.
A. said B. argued C. explained D. meant
Had electronic computers not been invented, many proble...
单项选择题Had electronic computers not been invented, many problems of space flight（）now.
A. could not have been solved B. could not be solved C. must not be solved D. should not have been solved
