21. —Would you mind if I closed the window?

—______. It’s that cold outside.

A. Sorry, I’m afraid             B. Yes, help yourself

  C. Sorry, you don’t            D. No, go ahead

22. —I called you many times yesterday morning, but I couldn’t get through.

—Oh. My brother ______on the phone all the time!

A. was talking                     B. has been talking            C. has talked               D. talked

23. ______the website of the Fire Department in your city, and you will learn a lot about firefighting.

A. Having searched             B. To search                C. Searching               D. Search