Question

【题目】A recent research shows that there _____ volcanic activities on the moon and Mars. However, they no longer exist now.

A. had been B. has been C. were D. would be

Answer 1

【答案】C

【解析】

试题分析：考查时态。根据下文的However, they no longer exist now.可知，现在它们不再存在了，故可以判断是曾经存在，故使用一般过去时，选择C。句意为：最近的研究表明在月球和火星上曾经有火山运动。