BBC环球慢速英语 第322期:一个人类基因组(3)

voice 1: When scientists first began to study DNA they could not see very much. The technology they used was not powerful enough. Later, technology improved. Technology could then help the scientists get a better look at DNA.
声音1：当科学家最开始研究DNA时，他们没有发现太多信息。他们所使用的技术不够强大。后来，技术革新了。改进后的技术能帮助科学家更好地了解DNA。

voice 2: In the 1950's scientists discovered that DNA was a kind of chain. This chain had millions of very small chemical substances linked together. They discovered that these substances formed DNA. But there was too much information in DNA for them to write down and study.
声音2：上世纪50年代，科学家发现DNA是一种链状结构。这种链状结构包含数百万种连接在一起的微小化学物质。他们发现这些是组成DNA的物质。但是，DNA有太多供科学家记录并研究的信息。

voice 1: They did know that the chain of DNA is made of four important chemical substances. Scientists gave each of these substances short names. Their short names are A, T, C, and G. The order of these letters, or substances tells a body how to grow and act. It is called a DNA code.
声音1：他们知道DNA由4种重要的化学物质构成。科学家给这些物质取了简短的名字。分别是A、T、C和G。这些字母或这些物质的顺序决定了一个人的生长和行为模式。这被称为DNA密码。