Question

【题目】The sky is much bluer ________ we have taken action to protect the environment.

A.becauseB.beforeC.untilD.unless

Answer 1

【答案】A

【解析】

句意：天空更蓝了，因为我们已经采取行动保护环境。A. because因为；B. before在……之前；C. until直到；D. unless除非。根据下文we have taken action to protect the environment.可知这里是表示原因。根据题意，故选A。