Loulan is believed ____ by sandstorms from AD 200 to AD 400.
| A．to be gradually covered over |
| B．to have been gradually covered over |
| C．being gradually covered over |
| D．having been gradually covered over |
The play had already been on for quite some time when we __ at the New Theatre.
| A．have arrived | B．arrived | C．had arrived | D．arrive |
Once again he didn’t hand in his homework _____ he had been given enough time to do it．
| A．in case | B．as though | C．so that | D．even though |
--- They live on a busy road．
--- There ______ be a lot of noise from the traffic．
| A．must | B．may | C．would | D．could |
_____ the chapter four times, I finally understood the author's theory．
| A．Reading | B．Having read | C．To read | D．Read |
．Don’t you think it is unfair for about two thirds of the population to have no_____ to health care?
| A．access | B．basis | C．entrance | D．guarantee |