一切物质都由分子组成，而分子由原子组成。

All bodies consist of molecules and molecules consist of atoms.

人们已经发现各种物质都是由原子组成的。

It has been found that all kinds of matter consist of atoms.

每个物质都是由原子组成的。

Every substance is made up of atoms.

该理论假设所有物质都是由原子组成的。

The theory postulates that all matter is composed of atoms.

物质由分子组成，而分子则是由原子组成。

Matter is composed of molecules that are composed of atoms.

一切物质从根本上说都是由原子组成的.

All matter ultimately consistsof atoms.

我们现在知道人的身体是由原子组成的

As we nowadays know, human bodies are made up of atoms.

没有任何恒星和行星。而气体只由原子组成，这些原子属于最简单的元素。

There were no stars and no planets. The gas was made up only of atoms belonging to the simplest elements.

你或许知道所有东西都是由原子组成的，而原子本身是一个非常非常非常小的粒子。

You probably know that all stuff is made up of atoms and that an atom is a really, really, really, really tiny particle.

我们都熟悉这样一个概念，即一切物质均由原子组成。

We are familiar with the idea that all matter consists of atoms.