英語の文法ミス教えてください

Historically, capital punishment has been for murder is widely used all over the world. A lot of people believe that capital punishment can refrain a case of murder, however, opponents believe the capital punishment is evil. There are three reasons, considering its immoral, not effective and practical aspects.
First, capital punishment is immoral. Opponents believe that a thought of killing murder is a bad thing, even murders killed people. They always regard killing people as evil.
Second, opponents insist that capital punishment is absolutely ineffective way of stopping the case of murder. According to scholar, they clamed that the death penalty is only as effective as the long-term imprisonment.
Third, the death penalty is unfair. Racial prejudice sometimes makes judgment unfair. For example, white people tend to give a big penalty to black or another colors.

No.1 ベストアンサー 回答者： marbleshit 回答日時： 2014/04/07 15:48

According to scholar, → According to scholars,

No.2 回答者： oignies 回答日時： 2014/04/07 23:48

一行目のisいらないのではないでしょうか。

あとrefrainもつかいかたがへんなきがする。人が何々するのをつつしむ、ひかえるというときの主語はひとだとおもうので。