21£®— May I use your computer to send an e-mail?

—___________!

A. Come on         B. Take care            C. Go ahead          D. Hold on

22. It will be at least 10 days ____________ they finish cleaning up the typhoon-stricken village.

A. until                 B. before               C. since                   D. when

23. The hostess kept talking with her mouth full of food, _________ all the guests embarrassed.

A. leave                B. left                   C. to leave             D. leaving