The development of the city's industry __________ its environment pollution.
| A．has added up |
| B．has added to |
| C．has added up to |
| D．was added to |
complete
| A．scene | B．elect | C．student | D．respect |
citizen
| A．uncle | B．ocean | C．rescue | D．percent |
laugh
| A．daughter | B．neighbour | C．enough | D．though |
Not once ________ to Michael that he could one day become a top student in his class.
| A．occurred it | B．it did occur | C．it occurred | D．did it occur |
— I don’t understand why you didn’t go to the lecture yesterday afternoon.
—I’m so sorry. But I _________ my homework.
| A．had done | B．was doing | C．would do | D．am doing |