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

玛莎，这些是给我家乡的亲友的信件......封信！

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

三月来封信 这是第一封提到凯萨琳琼斯的？

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 字母的字。

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

我听到最后字母是dubba-you，ex，why，zee。

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

这遗传密码简单的字母表组成，字母，A，T，C和G （碱基）。

Sometimes three or four letters together can make one sound.

有时三字母在一起可以出一声。

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

想象一下， 如果英文字母表有字母会是什么样子。

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字母的单词。

And it's just a cool four letter word.

这只是一很酷的字母单词。

Can you fit that into your four letter code?

你能把它放入你的字母代码中吗？

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

所以这星球上的所有生命都是 ATCG 构成的，即 DNA 的字母。

Ziggy had scrawled four letters across the page.

齐吉在页面上涂鸦了字母。

Hey, what's a four- letter word for cut?

嘿, 什么是字母的切割词?

" Fast" has four letters and four sounds.

“快”有字母和声。

We also have another radio station, called " KNBC." Usually radio and television stations have four letters.

我们还有另一广播电台，叫做“KNBC” 。 通常电台和电视台有字母。

Part four: letters and sounds are not always the same thing.

第部分：字母和并不总是一回事。

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4被称为核苷酸的基本物质组成。这就好比一只有4字母的字母表。

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，实际上是字母。

The call signs in the U.S. all have four letters for the radio and TV stations, or almost all of them.

美国的呼号都是广播电台和电视台的字母， 者几乎全部。

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.

在能够写出字母后，我便告诉任何一会写字的男孩，说我能写得和他一样好。