The two girls are so alike that strangers find difficult to tell one from the otherA. it

问题补充：

The two girls are so alike that strangers find difficult to tell one from the other．

A. it

B. them

C. her

D. that

答案：

(答案→)A. it

B. them

C. her

D. that

解析：考查形式宾语。It是形式宾语，代替真正的宾语to tell one from the other。句意：那两个女孩是如此的相似，以至于把她们区别开是很困难的。