21. At the age of five, ____________.

     A. he went to America                              B. his father died   

C. a car knocked him down                      D. All the above

22. I’ve been _____ for a better job since Christmas.

   A. looking round     B. looking out           C. looking up             D. looking at

23. The children have been playing with my hat — they’ve knocked it out of ______.

   A. control            B. size                     C. shape                  D. line

24. —— Do you intend to study English next term?

   —— Yes, ________.

   A. I intend          B. I intend to           C. I intend that          D. I intend so

25. Scientists _______ in many ways ________ their contributions ________ the development and progress of human society.