A recent research shows that there _____ volcanic activities on the moon and Mar

题干

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

上一题下一题 0.4难度单项选择更新时间:2015-06-24 05:59:39

小学学科试题库

初中学科试题库

高中学科试题库