reciprocating motion

• 往复运动

reciprocating motion的用法和样例：

例句

1. The steam-engine piston makes a cyclic motion.
   蒸汽机活塞做往复运动。
2. It cannot allow the link to translate on the horizontal direction, thus enabling the link to do reciprocating motion.
   不能让杆子的中心点左右移动，才能做往复运动。