17．The movie is to deucate people about environmental problems ______ our planet.
| A．threatened | B．being threatened | C．threatening | D．to be threatened |
It seems as if the sun ____ round the earth since it rises in the east and sets in the west.
| A．circles | B．is circling | C．has been circling | D．were circling |
I can’t find my dictionary now. Tom must have taken it by mistake, ______?
| A．mustn’t he | B．doesn’t he | C．didn’t he | D．hasn’t he |
Many a student ____ going to have themselves ______ in the hospital.
A, is ; to examine B. are ; examine C. is ; examined D. are ; examining
The ship would have sunk with all on board ______ for the captain.
| A．if it was not | B．had it not been | C．if it has not been | D．not had it been. |
Sitting at the back of the room but in front of some old men and women ______ a very shy girl with two bright eyes.
| A．was | B．were | C．are | D．being |