The government has taken some measures to solve the shortage of electricity but it may b

问题补充：

The government has taken some measures to solve the shortage of electricity , but it may be some time the situation improves.

A. since

B. when

C. before

D. unless

答案：

A. since

B. when

(答案→)C. before

D. unless

解析：考查固定句型。It be 一段时间before 从句，表示一段时间以后某事才发生。Before时间状语从句里用一般现在时表示将来时，主句里可以使用将来时或者情态动词。句意：也许一段时间以后情况才会改善。