Question

【题目】He made a mistake, but he took action to change the situation________ it got worse.
A.until
B.unless
C.before
D.since

Answer 1

【答案】C
【解析】句意：他犯了一个错误，但是在变得更糟糕之前，他采取了措施改变了这种情况。A. until直到；B. unless 除非；C. before在…… 之前； D. since自从。根据句意故选C。