Gamma-amino butyric acid, or GABA, for example, is a chemical thatshuts down nerve cells.

如γ-酸或伽马酸，都是可以使神经细胞关闭的化学物质。

The small orange-colored " fruit" is, in fact, ginkgo seeds, which have several layers. The fresh outer layer has butyric acid, the main source of the smell.

银杏果有好几层外皮，鲜的外果皮含有酸——也是它臭的主要来源。

And any given odorant, like this pizza, is made up of hundreds of different chemicals that you can smell, like the thymol of the oregano, the butyric acid of the cheese, and the acetylpyrazine of the crust.

任何特定的，如这个披萨，是由你能闻到的数百种不同的化学物质组成的，如牛至的百里香酚，奶酪的酸，和外皮的乙酰吡嗪。