a majority of students tends to

Movies and television must be the main 'causes'  수 일치

answered that they imitated fight  시제 일치

여기서는 꼭 시제 일치를 할 필요가 없다고 생각됩니다.

대답한게 과거고  따라한게 현재라면 이치에 맞지 않는다고 생각합니다.
따라한게 먼저이기에  나중에 대답할수 있다고 생각합니다.

answered that they imitated fight (따라했었다고 대답했다)
or
answered that they have imitated fight (따라한 경험이 있다고 대답했다)

9번째 줄, seem to be cool -> seem cool (제안)
11번째 줄, Since, -> Since
15번째 줄, was year 10 -> was in year 10 (제안)
16번째 줄, spent -> spending (제안)

제안이라 써있는 것은 확실하지 않습니다. 고쳐준 것 중 틀린 게 있으면 알려주세요. ^^
Ctrl + F 를 쓰면 틀린 부분을 찾는 게 더 쉬워요.

when I was year 10--> when I was in 10th grade
spent time on studying--> spending time on studying

똑같은건 그만올려 이제부터 중복되는건 올리지마요

The question as to whether movies and television have negative effects on young people or not has been a constant debate in the field of education. In reality, a majority of students tends to argue that movies and television do not have any negative effects. However, I believe that it is better for students to inhibit watching movies and television for several reasons.

First, violent contents from movies and television have a bad influence on young people. Teenagers cannot clearly distinguish right and wrong, so they accept various contents without hesitating even though they are violent. Moreover, young people tend to imitate these scenes, which leads to irrevocable results. According to some researches, 64 percent of young people answered that they imitated fight scenes from movies. Besides, they proudly said that these scenes seem to be cool. In modern society, teenager violence is a social issue. Movies and television must be the main causes of this result.

Second, young people are easily addicted to movies and television. Since young people are premature, they cannot control themselves. Young people generally study in school. Therefore, they have to concentrate on their academic courses, but addiction deters students from focusing on their studying. Some students have hard time inhibiting urges to watch movies and televisions, as they are already addicted to them. In my experience, when I was year in 10, I was crazy with movies and television. So, I spent time on watching movies and television rather than spending time on studying. At the end of the semester, I got bad scores on all subjects. This example clearly shows that movies and television have negative effects on young people.

The question as to whether movies and television have negative effects on young people or not has been a constant debate in the field of education. In reality, a majority of students tends to consider movies and television as a way of education. However, I believe that movies and television do not have any beneficial effect.

First, violent contents are dominating in movies and television. A serious problem is that young people are easily accessible to violent media. However, they cannot clearly distinguish right and wrong, so they accept various information through observation without a second thought including aggressive one. Young people nay even tend to imitate actions in scenes, which leads to youth violence. According to a survey, 64 percent of young people answered that they have mimicked fight scenes from movies. Besides, they proudly said that these scenes seem cool. Violent contents displayed in media tragically cause young people to have a wrong set of values. In modern society, adolescent violence has become a social issue. The main cause must be the media. Consequently, young people should be kept away from movies and television.
Second, young people are easily addicted to movies and television. Since young people are premature, they cannot control themselves. As a result, addiction to watching television distracts students from studying. Therefore, though studying is students' original tasks, they even have hard time inhibiting urges to watch movies and television. In my experience, when I was in year 10, I was crazy with movies and television. So, I spent time on watching movies and television rather than spending time on studying. Needless to say, I did not focus on my school works. At the end of the semester, I got bad scores on all subjects. Shocking by that, I declared to myself that no more watching television and movies in my life. Without watching them, I got straight A on all subjects in the next semester. This example clearly shows that addiction to watching movies and television deters young people to put their mind in studying.