A neutron contains two down quarks and one up.

一个中子包含两个下夸克和一个上夸克。

A proton contains two “up” quarks and one “down” quark.

质子包含两个“上” 夸克和一个“下” 夸克。

A proton is made of two up quarks and one down quark, and a neutron is two down quarks and an up quark.

质子由两个上夸克和一个下夸克组成，中子由两个下夸克和一个上夸克组成。

But the important thing here is that the up and down quarks are much lighter than the other four, like charm and strange.

但这里重要的是，上下夸克比其他四个要轻很多，喜欢魅惑和奇异。

Up and down quarks are the constituents of protons and neutrons, but there are two further pairs (or " generations" ) of quarks of different flavours: charm and strange, and top and bottom (also known as truth and beauty).

上夸克和下夸克是质子和中子的组成部分，但还有两对（或“一代” ）不同口味的夸克：魅力夸克和奇异夸克， 以及顶夸克和底夸克（也称为真夸克和美夸克）。