The problem is difficult for a little girl to

问题描述:

The problem is difficult for a little girl to
A.work out B.work it out C.work out it

A.
若加"it",只能理解为"problem",会导致句子结构混乱,无法理解.
但可以说"It is difficult for alittle girl to work out the problem."其中"it"是形式主语,不是指"problem",而是指整个后面的"for alittle girl to work out the problem".