第 29 课: 交通信号-1

The cars are going uphill and are almost at the top. 滑车在往上爬，几乎要到顶端了。

Some of the cars are going uphill, and some of the cars are going downhill. They are not upside down. 有些滑车在往上爬，有些滑车在往下滑，它们没有颠倒滑行。

All the cars are going downhill. 所有滑车都在往下滑。

The cars are upside down. 滑车颠倒滑行了。

The cars are going to be at the top soon. 滑车快要到顶端了。

The cars are at the top and are starting to go downhill. 滑车到了顶端，并开始往下滑。

The cars are going downhill fast. 滑车快速地往下滑。

The cars are going around a curve. 滑车在转弯。