高中学历解放军武警士兵考军校-英语特殊句型（五）

 21.陈述部分的主语为从句时，问句部分的主语一般用it代替，如：

①What he said is true, isn't it? (不用didn't he?)

②Where we will build the dam has not been decided yet, has it? (不用won't we?)

22.陈述部分的主语为动名词或不定式时，问句的主语用it代替。如：

①To do one good deed is easy for a person, isn't it?②Skating is your favorite sport, isn't it?

23.陈述部分的主语是不定代词one，反义疑问句的主语可以用one，也可以用you。如：One should be ready to help others, shuldn't one?