问题
选择题
It is uncertain ______ side effects these weight-loss drugs will bring about, although hundreds of thousands of patients have taken it.
A．that
B．whether
C．how
D．what
答案
答案：D
这句话考查的是主语从句，it是形式主语，因为是uncertain，所以主语是不确定的事，side effects缺少修饰，填what。句意是：虽然几十万患者采取了这些减肥药但是不确定它会产生什么副作用。选D。