问题补充:
I’m not sure if he in this exam. But if he harder, he will do better.
A. succeeds; works
B. will succeed; will work
C. will succeed; works
D. succeeds; will work
答案:
A. succeeds; works
B. will succeed; will work
(答案→)C. will succeed; works
D. succeeds; will work
解析:句意:我不确定他是否能在这次考试中成功;但是如果他工作得更努力,他会做得更好。本句中两个if 的意思并不一样。第一个if 意为是否,引导宾语从句,根据句意可知,考试还没进行,故用一般将来时;第二个if 意为如果,引导条件状语从句,从句中用一般现在时,主句用将来时。故选C。