【题目】The two girls are so alike that strangers find _____ difficult to tell one from the other.
A. itB. themC. herD. that
在线课程【答案】A
【解析】
试题分析：考察形式宾语。句意为：这两个女孩长得如此相像，以致于陌生人觉得很难把她们区分开。本句中it用在find后作形式宾语，真正的宾语是后面的动词不定式短语to tell one from the other。them，her，that等词均不能作形式宾语或形式主语。