In US colleges, a curve is the way that an exam’s score (90/100) is converted into a letter-grade score (A=3.85 and above). It is based on the overall performance of the class, and defines the boundaries between A, B and C. A curve wrecker scores much higher than anyone else and makes it harder for others to get an A.
curve wrecker：就是指某個學生的成績很高，被當做標杆來決定其他人的成績。
curve是美國大學考試中一種對原始成績（raw score）結合綜合分佈的修正措施，curve wrecker就是指某個學生的成績很高，被當做標杆來決定其他人的成績，也就是wrecker（肇事者）——符合我們所謂的「學霸」的定義。
在美國的大學中，考試分數會被換算成A，B， C不同的等級。每個級別根據全班同學的成績來劃定。但是，如果某位同學的成績特別出色，就會拉高A級的下限，其他同學因此很難拿到好成績。成績這樣好，甚至影響到了級別劃分，這樣的考神自然是學霸無疑了！
In US colleges, a curve is the way that an exam’s score (90/100) is converted into a letter-grade score (A=3.85 and above). It is based on the overall performance of the class, and defines the boundaries between A, B and C. A curve wrecker scores much higher than anyone else and makes it harder for others to get an A.