问题
选择题
It is uncertain side effect the medicine will bring about, although about two thousand patients have taken it.
A．that
B．what
C．how
D．whether
答案
答案：B
考查宾语从句。宾语从句中 bring about后缺少宾语，故用what 作定语修饰side effect，句意：还不清楚这种药会带来什么样的副作用，虽然大约两千名病人已经服用过。故选B。