－Why didn’t Susan come to see us yesterday as she promised?
－______.
| A．She must be busy | B．She might have been free |
| C．She must have been busy | D．She can’t be free |
We ________ the problem for a long time, but we didn’t reach any agreement.
| A．argued | B．explained | C．shared | D．communicated |
China sent up two manned spaceships and they were also great scientific _______ in the world.
| A．campaigns | B．surprises | C．achievements | D．discoveries |
She is one of the few girls who _____ in the kindergarten.
| A．is well paid | B．are well paid | C．is paying well | D．are paying well |
Every means _____ prevent the water from _____.
| A．are used to; polluting | B．will be used to; polluting |
| C．is used to; polluted | D．is used to; being polluted |
Not only I but also Jane and Mary ____ tired of having one examination after another.
| A．is | B．are | C．am | D．be |