Question

Something as simple as _____ vegetables in childhood may hel

Answer 1

A是eat 的不定式形式,B是动名词,C是将来进行时,D be eaten是被动语态,被吃.

由句子可以看出空格部分在句子中主语,是个选项中A、B可以做主语.

to do做主语和doing做主语的区别：

1.to do 一般情况下是用it做形式主语.例：It is rude to turn your back to your teacher and refuse to answer.

2.动名词作主语表示一般或抽象的多次性动作,不定式作主语表示具体的或一次性的动作,特别是将来的动作.例如：

_______ is a good form of exercise for both young and old．

这里不能写to walk,而只能是walking.