Okay, so let's just apply it to HCN.

拿HCN来举例看看
So if carbon has four, that makes possible a single bond to hydrogen,

碳有四个电子其中一个和氢成单键
a triple bond to carbon.

剩下的和氮成三键
Everybody has their octet except hydrogen that only wants two.

碳氮凑足八电子而氢只需要两个电子
So everybody's happy.

这叫皆大欢喜
And we can abbreviate it this way, and leave the dot.

我们可以把点简化掉
Lewis actually thought of drawing a colon, a pair of dots,

路易斯想到了用冒号即两点
to denote an unshared pair.

来代表未成对电子
So that's his notation.

这是他的写法
So NH3. Bingo!

NH3 就是这样写
How about BH3?

BH3呢
Just fine.

一样的