Question

We'll have a picnic in the park this Sunday ________ it rains or it's very cold.

A．since

B．if

C．unless

D．until

Answer 1

C

句意：除非下雨或天很冷，我们将在本周日去公园野餐。从句子之间的逻辑关系判断此处应为否定条件句，相当于if...not，故排除if，而选unless。A项since表因果关系。D项until只能引导时间状语从句，故排除。