到底什么时候用put on 什么时候用put it on

题目

到底什么时候用put on 什么时候用put it on
this pair of boots is too small for the boy to _____
a.put it on B.put on 选B.为什么不选A呢.
this pair of boots is so small that the boy can't ______
A.put it on B.put on 这道题应该选A.是因为后面缺少宾语对吗?

答案

this pair of boots is too small for the boy to put on不选A是因为这句句子不带有从句,是单句,各种成分只能有一个.it和this pair of shoes重复.this pair of boots is so small that the boy can't put it on 这是...