21 I learn English         taking notes in class.

A.  with                  B.  by                   C.  on

22.Please concentrate on your typing, and stop       out of the window.

A. to look                B.  look                 C. looking

23.English         all over the world.

A. speaking               B. speaks                C. is spoken

24.Mary         be in the classroom because I saw her in the library only a few minutes ago.

A. mustn’t               B. might                 C. can’t

25.This pair of trousers are          short for me.

A. too much               B. much too              C. very too