Kenney says the rubber is very solid - probably harder than a running track.

人行道上所用的橡胶其实十分坚固。甚至可能比田径场上的跑道还要硬一些。

youdao

Kenney says the rubber is very solid - probably harder than a running track.

人行道上所用的橡胶其实十分坚固。甚至可能比田径场上的跑道还要硬一些。

youdao