swing back and forth的意思|示意

Like magic out of a Harry Potter novel, such a metal could contract on command, or swing back and forth like a pendulum.

像这种仿佛出自《哈利·波特》小说中的魔法一般的金属可以按照指令收缩，或者像钟摆那样前后摇摆。

The girl sat on a swing, swinging back and forth.

那个女孩坐在秋千上，前后摇摆。

Show her how to swing her body back and forth, then teach her how to let go and fall properly to the wood chips below (with your help, depending on her age.)

向她示范怎样把身体晃来晃去，然后放开手之后安然地落在下面的木屑上(根据她的年龄，提供你的帮助。)

The central meaning shared by these verbs is . to swing back and forth boldly and dramatically.

这些动词所共有的中心意思是。大胆而有戏剧性的前后摆动。

Unless a child keeps pumping a swing, the back-and-forth motion decreases;

荡秋千的小孩除非不停地屈伸，否则秋千的运动就会因阻尼而停止；

Will no longer feel that life is too monotonous and old-fashioned as if the old house back and forth of that only know how to swing the pendulum clock units.

不会再觉得生活古板单调得犹如老房子里的那台只知来回摇摆的摆钟。