I failed in the examination last term and only then ____the importance of study.
| A．I realized | B．I had realized | C．had I realized | D．did I realize |
—Could I have a word with you，mum?
—Oh，dear，if you ________.
| A．can | B．must |
| C．may | D．should |
It is important to know about the cultural differences that ________ cause problems.
| A．must | B．dare |
| C．may | D．shall |
—Did you go to the fashion show last week?
—I ________，but I was fully occupied the whole week.
| A．must go | B．must have gone |
| C．would go | D．would have gone |
I’m as busy as a bee；________ you bother me with so many questions now?
| A．may | B．must |
| C．can | D．shall |
—I called you at 9 last night，but no one answered.
—Sorry，I ________ sleeping.I went to bed very early.
| A．need have been | B．would have been |
| C．must have been | D．should have been |