I’m sorry I didn’t see you when you entered — I ______ my homework.
| A．am checking | B．was checking | C．has checked | D．checked |
is no doubt that the Great Wall is one of the wonders of the world.
| A．There | B．It | C．This | D．That |
— Whose Chinese vase is it?
— I have no idea, but I’m pretty sure it _______ the old lady.
| A．doesn’t belong to | B．belongs to |
| C．isn’t belonging to | D．belonged to |
Mike ________ his car, for he came to work by bus this morning
| A．can have found | B．could have found |
| C．can’t have found | D．mustn’t have found |
______ is known to all，the Amber Room belongs to the Russians.
| A．As | B．Which | C．It | D．What |
_____ these experiments were successfully completed would we think of
going into humans.
| A．If only | B．So that | C．Only if | D．Even if |