Many studets get tired because they have to do too much homework.And thet（拼错了they） have no time too (改为to) do exercise,(这儿算一句结束.)so(大写So,开始另一句) ,(删掉这个逗号)they can't get good（改为high） grades,and they are not strong.I think it is very important to stay healthy,it（这儿最好重新开始另一句.It） depends on how often you do exercise.Our school has many kinds of sports (运动项目不能这么说,建议改为sportsequipment运动器材,因为你后面的球都算器材) like（suchas） basketball,volleyball and soccer.We often play sports(做运动不能这么说,改成doing exercise) in school.We can （要加一个do在这儿）exercise in P.E class.I think it is good for our health.It helps me too (又写错to) keep healthy.I hope we can have a lot(删掉) more time to do sports.