reciprocate
/rɪˈsɪprəkeɪt; rɪ`sɪprəˌket/ v
1 [I, Tn] (fml 文)
(a) give and receive (sth) in return; exchange (sth) mutually 互给（某物）; 互换（某物）.
(b) return (sth done, given or felt) 回报以（某种动作、 物品或感情）
He reciprocated by wishing her good luck. 他也祝她交好运.
I reciprocate your good wishes. 我也同样祝福你.
2 [I] (of parts of a machine) move alternately backwards and forwards in a straight line （指机件）沿直线往复移动
a reciprocating saw 往复式锯
reciprocating pistons 往复式活塞. Cf 参看 rotary 2.