问题补充:
I don’t know if he us; if he , I’ll let you know.
A. will come and help; comes
B. comes and helps; will come
C. will come and help; will come
D. comes and helps; comes
答案:
(答案→)A. will come and help; comes
B. comes and helps; will come
C. will come and help; will come
D. comes and helps; comes
解析:第一个if的意思“是否”,引导宾语从句,根据句意应该用将来时态。第二个if的意思“如果”,引导条件状语从句,从句用一般现在时态代替将来时态,所以答案A。