原子由中子、质子与电子组成。质子和中子曾经一度被认为是基本粒子。所谓基本粒子就是指不可再分割成更小的东西。
Atoms are made of neutrons, protons, and electrons. It was once thought neutrons, protons and electrons were fundamental particles. Fundamental particles can not be broken up into anything smaller.
所有的物质都是由称之为原子的微粒组成，而原子本身则由更小的微粒，电子、中子和质子所组成。
All matter is composed of tiny particles called atoms, which are themselves composed of smaller particles, electrons, neutrons and protons.
这些可见的普通物质由质子、中子和电子组成。
These visible, ordinary matters are composed of protons, neutrons and electrons.
锂原子是由三个电子、三个质子和四个中子组成的。
The atom of lithium is made up of three electrons, three protons and four neutrons.
锂原子是由三个电子、三个质子和四个中子组成的。
The atom of lithium is made up of three electrons, three protons and four neutrons.
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