Okay. Then you can look at how many things like cows are raised in the United States, and how many acres there are of carrots, or wheat, or corn, or whatever it is.

好了,然后就可以看看,比如,美国养了多少头牛,种植了多少英亩的胡萝卜,小麦,玉米,或其他东西

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选