As a stopping point on the famous Silk Road, Loulan is believed __________ by s

题干

As a stopping point on the famous Silk Road, Loulan is believed __________ by sandstorms from AD 200 to AD 400.

A．to be gradually covered over	B．to gradually cover over
C．to have been gradually covered over	D．to gradually have covered over

上一题下一题 0.4难度单项选择更新时间:2017-06-30 01:28:55

小学学科试题库

初中学科试题库

高中学科试题库