Directions: For each blank in the following passage, there are four choices marked A, B, C and D. Choose the one that is most suitable and mark your answer by blackening the corresponding letter on the Answer Sheet.
Times have changed and the ideas of the young and the old about the same thing are often ill contra diction. For example, parents and teenagers often disagree about the amount of freedom and responsibility that young people (21) to have. The teenager is more independent and often wants to be (22) to choose his own friends, select his own courses in school, plan for his own vocational (23) , and earn and spend his own money, and generally (24) his own life in a more independent (25) than many parents are able to (26) .
Most problems (27) teenagers and their parents yield to (导致) (28) planning and decision making. Within ally particular family, (29) are avoided and problems are solved when all of the persons take (30) in the situation, and (31) in working it out. (32) parents and young people learn how to get (33) well with each other and develop skills in understanding and (34) understood, even (35) most difficult problems are relieved and a situation might appear that teenagers and their parents can some times see eye to eye.
21. A. is
B. should
C. will
D. are