Question

We are going to have the sports meeting ________ it ________ tomorrow．

1. A.
   if; rains
2. B.
   unless; will rain
3. C.
   unless; rains
4. D.
   when; will rain

Answer 1

C
选C。unless是“除非”的意思，相当于if not。当主句的谓语是一般将来时的时候，由unless引导的状语从句要用一般现在时。