- Have you heard of Loulan?- Of course. It is believed many years ago. [ ]A. tha

— Have you heard of Loulan?
— Of course. It is believed _____ many years ago. [      ]A. that it covered over by sandstorms
B. that it is covered over by sandstorms
C. to be covered over by sandstorms
D. to have been covered over by sandstorms

试题答案

D