translation.en: The reason I can tell you what opportunity cost is, is because one day when I was playing Super Mario Kart on my couch, my friend Emmet walked in, and he said, "How long have you been playing Super Mario Kart?"
translation.zh: 而我知道什么是“机会成本”，是因为 有一天我躺在沙发上玩“超级玛丽赛车”， 我的朋友艾米特走进来说， “你在这玩 ‘超级玛丽赛车’ 多久了？”