Something must be done to prevent our city ____ by thick smoke.
| A．to be polluted | B．from polluting | C．from being polluted | D．polluting |
The sky is clouding over；we can see there ________ a rainstorm.
| A．is going to be | B．is going to have |
| C．will be | D．will have |
Close the door of fear behind you，and you ________ the door of faith open before you.(2012·湖南)
| A．saw | B．have seen |
| C．will see | D．are seeing |
—Ann is in hospital.
—Oh，really？I ________ know.I ________ go and visit her.
| A．didn't；am going to | B．don't；would |
| C．don't；will | D．didn't；will |
I ________ in London for many years，but I've never regretted my final decision to move back to China.
| A．lived | B．was living |
| C．have lived | D．had lived |
In 1492，Columbus ________ on one of the Bahama islands，but he mistook it for an island off India.
| A．lands | B．landed |
| C．has landed | D．had landed |