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 |
____ the storm on the sea,it is reported that the president has put off the trip.
| A．thanks to | B．because of | C．due to | D．as a result |
____is known to us all,,things can easily go wrong when people are under______.
| A．Which;control | B．As; load | C．It; strength | D．As; stress |
We began to work in the fields. ____, it started to rain, so we went home.
| A．But | B．However | C．While | D．Yet |
First as a student, she went on___(become) a surgeon.
| A．to get | B．to be | C．to become | D．to turn |
He spoke for a long time but the meaning didn’t really _______.
| A．come out | B．came up | C．came across | D．came down |