One learns a knowledge by making mistakes and ______ them.
| A．corrects | B．correct | C．to correct | D．correcting |
---- How’s your new babysitter?
---- We ______ ask for a better one. All our kids love her so much.
| A．should | B．might | C．mustn’t | D．couldn’t |
----Please call me if there is a problem.
---- Thanks. I won’t ______ to ask for your help if I feel I need it.
| A．hesitate | B．bother | C．consider | D．doubt |
______ in diving suits, they walk around in this magic world, lighted by the lamps of the ship.
| A．Dressing | B．Dressed | C．To dress | D．Being dressed |
---- Who is it that is making so much noise upstairs?
---- ______ the students preparing for the New Year’s Party.
| A．There are | B．They are | C．It is | D．That is |
----What’s that smell?
---- I don’t know, but ______ it is, it’s terrible!
| A．whatever | B．however | C．whichever | D．wherever |