The Wheel
轮子
You probably see wheels underneath cars, airplanes, bikes and many other vehicles.
你可能看到过汽车、飞机、自行车和很多其他交通工具底下的轮子rCBA[8=iRUVPTsq。
A wheel is a kind of machine.
轮子是一种机器r=UP,&%=7j[SrgRX。

It is round, it moves along the ground.
它是圆形的，能沿着地面滚动T75Y^WJi1YiwL。
It helps people to move heavy things, also it helps people to travel faster.
它能帮助人们运送笨重的东西，也能使人们的旅行更快捷md&yDFxzz+xpqoB^Bq0。
Do you know when the first wheel was made?
你知道第一个轮子是什么时候制造出来的吗？
It was made around B.C.3500.
它大约是在公元前3500年制造的C3~kx%C^xkWQzn)XP7.。
At that time, it was made of wood.
那时，它是由木头制成的!-_sDYjCBplUR6nV。