这个句子：it took the students more than three hours to do their homework every day.主语太长时,it 充当形式主语,放在句尾,

题目

这个句子：it took the students more than three hours to do their homework every day.主语太长时,it 充当形式主语,放在句尾,保持平衡.不太理解,怎么讲是保持平衡?头重脚轻的情况下是什么情况?形式主语是怎么解释?

答案

这是英语语法术语.其实就是主语太长,后面太短,显得头重脚轻.比如主语to do.took me 2 hours.
前面主语是to do.看起来就很臃肿,有时候听话者听了半天不知道你要说什么.最好才听出来是to do.这件事花了我2个小时.所以干脆英语中就用it代指一件事（其实真正的事儿就是to do.),听话者一听就知道是it这件事花了我2个小时.至于是什么事,那就慢慢听.