[单项选择]　　Finishing teacher’s evaluations need maturity and objectivity. Every semester we have the opportunity to evaluate our instructors. We are supposed to judge their lectures, interest in students’’ problems, methods of assigning work, and general ability to conduct a class. Then, when the instructor has left the room, we must write our evaluations on the forms provided. We are not sup-posed to exchange view or discuss our responses. After everyone has completed the forms, one student collects and tallies the responses and then puts them in an envelope and makes them sealed. 　　It is very difficult to evaluate another person’s performance objectively. For example, Senta recently wrote irresponsible remarks about her instructor because she was falling to pass the course. Her friend Sam wrote a marvelous description of the same instructor because he received an A in the course. Both Senta and Sam were not fairly evaluating the instructor. They were affected by the grades they were earning
A. by discussing opinions with classmates
B. by rating the instructor’s interest in students’’ problem
C. by discussing opinions with instructors
D. by rating instructor’s humorous remarks