Question

I hope that the little ____ I have been able to do has been of some use. A. which

I hope that the little ____ I have been able to do has been of some use.
A. which B. that C. what D. for which
Which one? Why?

Answer 1

B. that

I hope that后面是宾语从句（中间的东西下面讲）has been of some use.

the little（that） I have been able to do
我希望， 我能够做到的那一点点， 会有些用。

little , only , the one ,the only one , first 等序数词。
有以上这些时，定语从句只用that ，不用which

Answer 2

B
the little是不定代词，不能用which