底线: to underline, bottom line, base line (in sports), baseline, minimum, spy, plant...
跟踪: to follow sb's tracks, to tail, to shadow, tracking...
碰撞: to collide, collision...
哈哈: (onom.) laughing out loud...
惊喜: nice surprise, to be pleasantly surprised...
激起: to arouse, to evoke, to cause, to stir up...