gain on someone/something
phrasal verb with gain verb [ I or T ] uk/ɡeɪn/ us/ɡeɪn/
逼近…；赶上…
to get nearer to someone or something that you are chasing
Garcia was gaining on her opponent throughout the race, but only overtook her at the very end. 加西亚在整个赛跑过程中一点点逼近对手，但直到最后一刻才超过了她。