（ ）26. I saw your son ____ football on the playground when I called you yesterday.
A. to play B. played C. playing
（ ）27.I always have great fun ______ sports.
A. to do B. do C. doing
（ ）28. --Would you mind ___ me English?
–Of course not.
A .to teach B. teaching C. teach
（ ）29.We will __ the school sports meeting next time.
A. join B. take part in C. be
