Yangyang: How did people travel many, many years ago, Baobao?

阳阳：许多、许多年以前，人们怎样旅行，宝宝？

Baobao: They walked or rode horses because there were no bikes, cars, or buses.

宝宝：他们步行或者骑马，因为没有自行车、小汽车和公共汽车。

Yangyang: There were no ships, trains, or planes.

阳阳：没有轮船、火车和飞机。

Baobao: Travelling in the old days was very slow.

宝宝：在过去旅行非常慢。

Yangyang: Yes, it was difficult and dangerous, too.

阳阳：是的，它还很困难、很危险。

Baobao: Do you know who invented those vehicles?

宝宝：你知道谁发明了那些交通工具吗？

Yangyang: Some smart people did. Their inventions make our life easy and comfortable.

阳阳：一些聪明的人发明的。他们的发明使我们的生活变得既轻松又舒服。

Baobao: They also make travelling safe and fast.

宝宝：它们也使旅行变得既安全又快捷。