I changed the conclusion part, or I can say I add something into the conclusion part. In the conclusion before, I repeated the thesis statement but and the end I did not conclude my opinion, cameras should be set. Comparing with body and intro, conclusion is still seemed too short, but I think if I try to repeat my idea, it will be fussy. I am think about adding some evaluation of students who think cameras are good in the next revision. It may improve my conclusion, but I am not sure it work or not.