—May I smoke here?
—If you ____, choose a seat in the smoking section.
| A．should | B．could | C．may | D．must |
Mr. Wang would have continued to lead _____ poor life instead of changing his lifestyle if he hadn’t met Mr. Smith by _____ chance who was a businessman.
| A．the; a | B．a; the |
| C．a; / | D．/; the |
There is still much to discuss. We shall, ______, return to this at our next meeting.
| A．so | B．however |
| C．because | D．Therefore |
Dr Yuan Longping grows _____ is called super hybrid rice, _____ has a high output.
| A．what; which | B．that; what |
| C．that; which | D．what; that |
---Do you want to come with us?
---No, I would rather ______ at home than _____ with you.
| A．to stay; go | B．to stay; to go |
| C．stay; go | D．stay; to go |
Only when it is hungry ______ a human being.
| A．a lion will attack | B．a lion should attack |
| C．will a lion attack | D．should a lion attack |