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。但是有这些编码中会出现错误。

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

一个词，几个，没标点，没表情包，就一个“好的”。

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

玛莎，这些是给家乡的亲友的信件......四封信！

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

现在他们找到好几个两个一样符号的 四个的。

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

听到最四个是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.

小写的那个——不像“OK”来自拉丁语或希腊语，用四个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.

在能够写出四个，便告诉任何一个会写的男孩，说能写得和他一样好。

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

然们听到它在城市路，然是路的右侧，们看到三个，哦，实际上是四个。

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个被称为核苷酸的基本物质组成。这就好比一个只有4个的表。

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

这个遗传密码由简单的表组成，四个，A，T，C和G （碱基）。

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

三个月来四封信 这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， 如果英文表有四个会是什么样子。

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

不要让太兴奋， 因为当兴奋会使用四个的单词。

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

那是一个大多数人不喜欢的四个的词。

And it's just a cool four letter word.

这只是一个很酷的四个单词。

Four letters four words. Four letters four words.

四个四个词。四个四个词。

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.

前四个S-E-A-M单独使用，构成一个名词。

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.

所以这个星球上的所有生命都是由 ATCG 构成的，即 DNA 的四个。