Question

My grandfather has a computer, but he doesn't know ________ to use it.

1. A.
   what
2. B.
   how
3. C.
   who
4. D.
   which

Answer 1

B
考查特殊疑问词加动词不定式的用法。根据本题题意选B。意为：我爷爷有一台电脑，但是他不知道怎样使用它。