Quadrivalency
n. 四价
🗣️ 情景例句
Will you please try to relax?
能不能放轻松些？
I'm stuffed.
我快撑死了！
it would be up and down, to and for and from side to side.
呈现出上上下下、来来回回、左左右右3种性质的运动。