Loulan is believed ____ by sandstorms from AD 200 to AD 400.
#70910
A
to be gradually covered over
B
to have been gradually covered over
C
being gradually covered over
D
having been gradually covered over
推荐题目
The dictionary published by Oxford University Press recently has really ______ because it is of great use to the learners of English.
#83945
A
taken away
B
taken down
C
taken off
D
taken out
You must ______ a wide vocabulary if you want to learn a language well.
#69288
A
set up
B
put on
C
settle down
D
build up