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

问题补充：

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

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：他们在屋内时刻备有蜡烛是停电的时候用的，因此该空应填in case引导目的状语从句。