If you ________ Beijing Duck，I'd like to treat you to a meal at a famous duck restaurant．
| A．didn't try | B．don't try | C．haven't tried | D．hadn't tried |
Two people were killed in the serious car _______ the other day.
| A．strike | B．break | C．crash | D．incident |
It is said that the temperature is unusual mainly _______ global warming caused by human activities.
| A．in spite of | B．by means of | C．in case of | D．on account of |
The transformation of our city will make _______ for people here to have a comfortable environment.
| A．it possible | B．no possibility | C．impossible | D．there was possibility |
Mary _______ her mother with the housework, but she didn’t.
| A．must have helped | B．ought to have helped |
| C．must help | D．should help |
The local government announced that only when the fire was under control ________ to return to their homes.
| A．the residents would be allowed | B．had the residents been allowed |
| C．would the residents be allowed | D．the residents had been allowed |