My parents live in a small village.They always keep candles in the housethere is a power c

问题补充：

My parents live in a small village.They always keep candles in the housethere is a power cut.

A. if

B. unless

C. in case

D. so that

答案：

A. if

B. unless

(答案→)C. in case

D. so that

解析：根据句意可知留蜡烛在家里是为了以防万一停电。in case意为“以防万一”；if 引导条件状语从句,意为“如果”；unless引导让步状语从句,意为“如果不”；so that引导目的状语从句,意为“为了”。