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

如γ-氨基丁酸或伽马氨基丁酸，都是可经细胞关闭的化物质。

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，鲜的外果皮含有丁酸——也是它臭味的主要来源。

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.

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