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，我們將在本周日去公園野餐。從句子之間的邏輯關系判斷此處應為否定條件句，相當于if...not，故排除if，而選unless。A項since表因果關系。D項until只能引導時間狀語從句，故排除。