So difficult _____it to live in an English-speaking country that I determined to learn English well.
| A．I have felt | B．have I felt | C．I did feel | D．did I feel |
—Can we ski on this mountain?
—Of course.However, at no time _______ you do so alone.
| A．could | B．might |
| C．need | D．must |
He _______ have completed his work；otherwise, he wouldn’t be enjoying himself by the seaside.
| A．should | B．must |
| C．wouldn’t | D．can’t |
He must have been late for the conference yesterday, _______?
| A．didn’t he | B．hasn’t he |
| C．mustn’t he | D．wasn’t he |
He _______ more visits to his parents.He has been regretting not doing so since they passed away.
| A．should pay |
| B．would pay |
| C．should have paid |
| D．would have paid |
Some aspects of a pilot’s job _______ be boring,and pilots often _______ work at inconvenient hours.
| A．can; have to | B．may; have to |
| C．have to; may | D．ought to; must |