I hope ____ the little ____ I have been able to do has been

I hope ____ the little ____ I have been able to do has been of some use .
A.that;that
B./;by which
C.what;that
D./;with which 翻译 详解、、

A
意思是：我希望我已经做了的那些小事能起一些作用.
是一个定语从句,答案带进去读就通了
再问： 详解、、 谢谢
再答： 英语这东西能有什么详解呃 i hope后面加that引导从句，句子还原后就是 I have been able to do the little。the little 应该就是指小事。定语从句中指代事物的就用that或which咯。 你要让我讲什么东西做什么成分的话我是不懂了。我的解题方法是把句意看懂