The two girls are so alike that strangers find difficult to tell one from the other. (2011·山东，24)
A. it
B. them
C. her
D. that
网友回答
A. it
B. them
C. her
D. that
解析： A
解析 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。