Question

  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

Answer 1

A

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。