The millions of calculations involved, __ by hand, would have lost a-考呗网题库移动版

单选题 The millions of calculations involved, __ by hand, would have lost all practical value by the time they were finished．

A． had they been done
B．having been done
C．they had been done
D．they were done

参考答案A

解析: A。涉及的数以百万次的运算，如果用手工来进行，到它们完成的时候，也就失去了所有的实用价值。考查虚拟语气。空格处为虚拟条件句省略了连词if，因此要部分倒装，还原后应为：ifthey had been done。

单选题 When you have finished that book, don't forget to put it on the bookshelf, ．__ ?

A．do you
B．will you
C．don't you
D．won't you

单选题 No bread eaten by man is so sweet as __ earned by his own labor．

A．one
B．what
C．such
D．that

单选题 The storm Sweeping over this area now is sure to cause __ of vegetables in the coming days．

A．rarity
B．scarcity
C．invalidity
D．variety