I have not seen him_____ he went to college.
| A．when | B．before | C．as | D．since |
The number of people invited ______ fifty, but a number of them _____ absent for different reasons.
| A．were, was | B．was, was | C．was, were | D．were, were |
When and where to go for the on-salary holiday ______ yet.
| A．are not decided | B．have not been decided |
| C．is not being decided | D．has not been decided |
Every possible means ______ to prevent the air pollution, but the sky is still not clear.
| A．is used | B．are used | C．has been used | D．have been used |
E-mail, as well as telephone,______ an important part in daily communication.
| A．is playing | B．have played | C．are playing | D．hoped |
---“Each of the students, working hard at his or her lessons,_____ to go to university.”
----“So do I.”
| A．hope | B．hopes | C．hoping | D．hoped |