禁止近亲结婚的目的是

Last term,Peter was ____ at home.His parents were doing busines in another city. He felt lonely,so he often turned on the computer and played computer ____. However, sitting in front of the computer for a long time is ____ for him. And he spent little time on his study.He failed his exams.Luckily,his parents ____ his problem in time.They decided to come back home.Peter studies hard now.So far,he has made progress in his study.He ____ he can catch up with his classmates soon.