_____________grades you get in this exam, you should never lose heart.
| A．No matter how | B．What | C．No matter what | D．Which |
Because of the heavy snow, we had to delay the visit until this weekend to the artgallery ____ in the center of our city these days.
| A．being held | B．holding | C．to be held | D．held |
While watching television, ____.
| A．the doorbell rang | B．we heard the doorbell ring |
| C．there was someone knocking at the door | D．the doorbell was ringing |
I’ll have all of the readings ____ by the end of this term if my plan goes well.
| A．completing | B．to complete | C．completed | D．being completed |
—How did it come that you damaged your car so badly?
—I ____into a tree on the roadside the other day.
| A．ran | B．had run | C．was running | D．run |
Air pollution, together with littering, ____ many problems in our large industrial cities today.
| A．causes | B．cause | C．caused | D．causing |