You may think of it as the free running piston in your vehicle's engine.

你可能会认为它当作免费的运行活塞在您的汽车的引擎。

youdao

You may think of it as the free running piston in your vehicle's engine.

你可能会认为它当作免费的运行活塞在您的汽车的引擎。

youdao