Wind is a current of air caused by a vacuum caused by hot air rising.

风是由热空气上升产生真空而引起的空气流动。

That's not just hot air.

那不仅仅是吹牛。

Are you full of hot air?

你在吹牛吗？

It uses hot air.

它使用热空气。

A balloon can fly in the air because hot air rises.

气球能在天空飞是因为热空气会向上升。