So DNA is a set of instructions for how our bodies work written using a chemical code of four letters – A, T, C, G. But sometimes the code contains mistakes.

那么，DNA就是A、T、C、G四种碱基编码组成的指示机体运转的遗传指令。但是有时编码中会出现错误。

One word, four letters, no punctuation, no emojis, just " sure."

一词，几，没标点，没表情包，就一“好的”。

Marsha, these are letters to my family and friends back at home......four letters!

玛莎，是给我家乡的亲友的信件......四封信！

They've got a repeating four- letter word ending with two symbols that stand for L.

现在他们找到好几两一样符号的 四的。

I heard that the last four letters were dubba-you, ex, why, zee.

我听到最后四是dubba-you，ex，why，zee。

A little one—it's not like OK comes from Latin or Greek and shows ignorance on the part of someone who spells it out with four letters.

小写的那——不像“OK”来自拉丁语或希腊语，用四拼写出来就暴露了某人的无知。

After I was able to make four letters, I would tell any boy who could write that I could write as well as he did.

在能够写出四后，我便告诉任何一会写的男孩，说我能写得和他一样好。

And then we hear it's on City Road, then the road to the right and we see three, oh actually four letters there.

然后我们听到它在城市路，然后是路的右侧，我们看到三，哦，实际上是四。

It was too simple. It had just four basic components, called nucleotides, which was like having an alphabet of just four letters.

它太简单了，主要由4被称为核苷酸的基本物质组成。就好比一只有4的表。

The code comes out to be a fairly simple alphabet, four letters: A, T, C and G.

遗传密码由简单的表组成，四，A，T，C和G （碱基）。

Four letters in three months and this is the first mention of Kathleen Johns?

三月来四封信 是第一封提到凯萨琳琼斯的？

Imagine what it would be like if the English alphabet had four letters.

想象一下， 如果英文表有四会是什么样子。

Don’t get me too excited because I use four letter words when I get excited.

不要让我太兴奋， 因为当我兴奋时我会使用四的单词。

And that's one four letter word that most people don't like.

那是一大多数人不喜欢的四的词。

And it's just a cool four letter word.

只是一很酷的四单词。

Four letters four words. Four letters four words.

四四词。四四词。

Takeaway four, letter writing is a hobby.

第四点，写信是一种爱好。

The first four letters, S-E-A-M, when used on their own, form a noun.

前四S-E-A-M单独使用时，构成一名词。

Can you fit that into your four letter code?

你能把它放入你的四代码中吗？

So all life on this planet is made in ATCGs, the four letters of DNA.

所以星球上的所有生命都是由 ATCG 构成的，即 DNA 的四。