One possible version：
Our school has made a survey about how long middle school students can fix their attention in class during each period．The result shows that only 40% of the students can draw their attention to the class, while the rest of them can not concentrate on the lesson．30% of the students think the problem is caused by all kinds of noises in the classroom; the other part of students consider the lack of sleep and tiredness as the major causes．
Therefore, we advise that the classroom be bright and the air inside stay fresh．As for students, they should try their best to be active in class in order not to be disturbed by others．During the breaks, they can take some exercises or have a little rest in the classroom．
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