加分英语翻译

楼主，应该这样翻译处理才是最地道的欧美表达方式：

15 points were additionally scored as the reward of (participating/winning) certain competition.

如果是因为参加某个比赛而加分，选participating
如果是因为赢了某个比赛而加分的，选winning

(someone)was added 15 points in the mid-term exam because of a certain match.

benefited from certain competition, fifteen scores are added to enterance examination of senior high school.

我可不敢说够不够地道，反正该翻的都翻了

Because of a game, plus a test in 15 points