We should treasure our friends by their aid when they are in troubleA.going to B.turning to C.dropping to D.failing to 为什么选择A4个选项的用法和区别?

We should treasure our friends by their aid when they are in troubleA.going to B.turning to C.dropping to D.failing to 为什么选择A4个选项的用法和区别?
We should treasure our friends by their aid when they are in trouble
A.going to B.turning to C.dropping to D.failing to
为什么选择A
4个选项的用法和区别?

We should treasure our friends by their aid when they are in troubleA.going to B.turning to C.dropping to D.failing to 为什么选择A4个选项的用法和区别?
理解句意：我们应当珍惜自己的朋友,当他们遇到困难时我们应当给予援手.
AB都是朋友帮你,而D是失败了,只有C选项符合题意