American students take part___________ different activities after school.

  A. at B. on C. in D. for

17. Nam is interested in___________ experiments in his free time.

  A. do B. does C. to do D. doing

18. Some students___________ blindmans bluff in the school yard now.

   A. are doing B. are playing C. is doing D. is playing

19. Howdo you go swimming after school?

   A. many B. much C. often D. far

20. We study different countries and their people in ___________.

    A. Literature B. History C.