因此，我们的身体不断地把旧物质替换成新的，就像一个喷泉，或多或少地保持着它的形式和运动，但其中的水分子总是不同的。

Thus our bodies continuously exchange old substance for new, just like a spring which more or less maintains its form and movement, but in which the water molecules are always different.

youdao

分子运动理论便是我们能找到的一个很好的例子。在这个理论中，气体被描绘成由许多不断运动的小颗粒组成。

A good example of this is found in the kinetic molecular theory, in which gases are pictured as being made up of many small particles that are in constant motion.

youdao

所有的物质都是由不断运动的原子和分子构成的。

All things consist of atoms or molecules, which are constantly moving.

youdao

所有的物质都是由不断运动的原子和分子构成的。

All things consist of atoms or molecules, which are constantly moving.

youdao