21. — Do you mind if I open the window?
— ______. We’d better let in some fresh air.
A. I’d rather you didn’t B. Yes, please C. No, please don’t D. No, go ahead
22. I meant abroad with them, but I didn’t have enough money.
A. go. B. to go. C. going. D. gone .
23. _____ from the plane, the Yellow River looks like a silk ribbon.
A. Seen B. Seeing C. To see D. Having seen
