teetertotter

1. Two people balance on a teetertotter more commonly than just one ( in the middle of the board), and sometimes two may swing together with one seated and the other standing and "pumping";
   两个人坐跷跷板比一个人玩更普遍（一个人坐在翘翘板中间），有时两个人一起玩时，一头坐，另一头站，“上下摆动”；
2. The results indicate that: siphon effect mainly supplies the matter and energy transformations, connected vessels effect is to start vertical movement 、 excitated gravity wave probably and produce phenomena of teetertotter, while narrow pipe effect is to increase velocity.
   结果表明，河西走廊连通器的虹吸效应主要是传输各种物质和能量，连通器效应是产生垂直运动、激发重力波和产生翘翘板现象，而狭管效应主要是增强风速。

noun

1. a plaything consisting of a board balanced on a fulcrum

   Synonym:    seesawteeterteeter-totterteeterboardtilting boarddandle board

verb

1. ride on a plank

   Synonym:    teeter-totterseesaw