I showed him __ pay attention to when he was buying a sencond-hand car.

题目

I showed him __ pay attention to when he was buying a sencond-hand car.
A.what to
B.how to
C.what
D.how

答案

C.what
后面已经有了to,所以AB排除.用what 是做(pay attention) to的宾语,如果用how的话,to 就没有宾语了.