get back at--报复
get back at (get revenge, get even) 报复,报仇============
● I am so hurt that I want to get back at him.
我受的伤害这么大,我要报复。
● When my boy friend broke up with me, I dated his best friend to get back at him.
当我的男朋友跟我分手后,我开始跟他最要好的朋友约会以作报复。