题目

Many teachers have come to realize that one of the keys ____ their students lose interests in their subjects is to changes ways of teaching.
A.to not letting B.not to let C.not to letting D.to letting not

提问时间：2021-02-04

答案

the key to ...意思是 ...的钥匙；...的关键.
这里的to是介词,所以要在介词后面进行否定,即 the key to not...
而 let 是实意动词,介词后面需要将其改为动名词,就是 the key to not letting.
选A