我们的身边有各式各样的交通工具，如果你要旅行，你最想乘坐哪种交通工具呢你在日常生活中关察到我们用的交通工具有:空中交通工具，如飞机。陆地交通工具如公共汽车，小轿车，火车，货车等等，还有水上交通工具如轮船，潜水艇还有许多我没做过的呢

We have all kinds of transportation around us. If you want to travel, which kind of transportation do you want to take most? You have noticed in our daily life that we use: air transportation, such as airplanes. Land vehicles such as buses, cars, trains, vans and so on, as well as water vehicles such as ships, submarines and many other things I haven't done

你们知道陆地交通工具的车轮为什么是圆的呢？我们常用积木做各式各样简单的简易车，做时我们就知道圆形的车轮省力，平稳，当我们真正做到真车上时，圆形的车轮开动在前行时能保持车内的平稳，使车内的乘客做车时‘舒服，即使在爬坡时，做在车上的人或物也不会感到颠簸的不舒适而难受。你们都知道这些常识吗，希望你们也了解车子！

Do you know why the wheels of land vehicles are round? We often use building blocks to make all kinds of simple cars. When we do it, we know that round wheels are labor-saving and stable. When we really do it on the real car, the round wheels can keep the stability of the car when moving forward, making the passengers in the car "comfortable. Even when climbing the slope, people or things in the car will not feel uncomfortable and uncomfortable. Do you all know these common sense? I hope you also know about cars!