The two men are so alike that strangers find ______ difficult to tell one from the other.
A.itB.themC.herD.that在线课程A
解析：
考查形式宾语。It是形式宾语，真正的宾语是to tell one from the other.句意：那两个人是如此的相似以至于陌生人发现要把他们分辨出来很难。