We know that about seventy percent _____ the earth _____ covered by water.
| A．/; is | B．of; are |
| C．of; is | D．about; are |
I can’t tell when that house exactly, but it must be very long ago.
| A．is built | B．will build | C．was built | D．has built |
— you out the physics problem, Kathy?
— Not yet, but I’m going to.
| A．Do; work | B．Will; work | C．Had; worked | D．Have; worked |
— John, could you please the black-board now? It’s your duty today.
— OK. I’ll do it right away.
| A．not to clean | B．to clean | C．not clean | D．clean |
— You used to the bus to school, didn’t you?
— Yes, I did. However, I am used to to school now.
| A．take; walk | B．take; walking | C．taking; walking | D．taking; walk |
— What other rules do you have in your class?
— Each student has to a composition once a week.
| A．hand in | B．hand up | C．hand over | D．hand out |