The science teacher，Mr．Black，had asked his students to study a particular animal．They were asked to write a short report and then make a
(1) in class．Some talked about dogs，others
(2) horses，and some chose fish．But the most
(3) discovery of all was made by little Sophie．
"I found that
(4) are terribly bad-tempered（坏脾气）"，she said for certain．
Everyone smiled，waiting for her to
(5) ．Then Sophie explained，"I spend hours
(6) flies．When they flew normally，everything was okay，
(7) when they found a window they would make a noisy sound．I had always thought they make that noise
(8) their wings，but they don't．With my daddy's telescope，I watched the flies really
(9) ，and saw that
(10) they were doing was shouting．They were angry because they
(11) fly out of the window．Later，a butterfly passing by the window tried to
(12) them the top of the window was open，but it had no effect at all．The flies just
(13) shouting．"
Mr．Black laughed and explained to the class that the flies'behavior had nothing to do with
(14) ．Instead，it was an example of animals having different levels of intelligence（智力）．At the
(15) of the class，Mr．Black asked the students to bring a list of animals in their order of intelligence．
What surprised Mr．Black was that many parents came to the school to
(16) the next day，
(17) their children had listed their parents among the least
(18) animals!This，said the children，was because their parents did
(19) but complain．
Mr．Black had to do a lot of explaining to calm the parents down．However，it also helped some of the parents
(20) that although they weren't stupid，they didn't often behave very intelligently．