What does the speaker mean a. These results prove that the quality of the teaching is not very good. b. These results are not convincing to prove anything. c. These results are not reliable to prove anything. d. These results are not obtained in a scientific way.

判断下面题中的两种量是否成正比例，并说明理由．

（1）速度一定，路程和时间．

（2）正方形的边长和它的面积．

（3）工作效率一定，工作总量和工作时间．