Tom is never afraid_____his opinions.A.to express B.of expression

问题描述:

Tom is never afraid_____his opinions.A.to express B.of expression
答案是选A.可是B为何不行呢?

选A
be afraid to do sth,be afraid of sth,这两个词组都是对的.但本句后面有个宾语his opinions,所以只好用动词,所以选A.为何不能接宾语了?