Question

It is rather difficult to make friends with her, but her friendship, _______, is

It is rather difficult to make friends with her, but her friendship, _______, is truer than any other’s.
A. while gaining
B. after gaining
C. when to gain
D. once gained

Answer 1

答案D
由句意可以得知，her friendship与gain是被动关系，省略了it is。