Question

It is uncertain ______ side effect the medicine will bring about , though about one thousand patients have taken it.

1. A.
   that
2. B.
   whether
3. C.
   what
4. D.
   how

Answer 1

C
试题分析：句意：尽管大约1000名病人使用了这种药，但它会带来什么样的副作用还不清楚。此处what修饰名词side effect。故选C。
考点：考查名词性从句的连接词。