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
考查连词。What“什么样的”做定语，限定side effect。“虽然两千多病人使用过这种药，但是会带来什么样的副作用还不确定。”