A man walks into a pub and says, "Give me three pints of Guinness, please."
So the bartender brings him three pints and the man proceeds to alternately sip one, then the other, then the third until they're gone.
He then orders three more, and the bartender says, "Sir, I know you like them cold, so you can start with one and I'll bring you a fresh one as soon as you're low."
The man says, "You don't understand. I have two brothers, one in Australia and one in England. We made a vow to each other that every Saturday night we'd still drink together. So right now, my brothers have three Guinness stouts too and we're drinking together."
The bartender thinks it's a wonderful tradition, and every week he sets up the guy's three beers as soon as he enters in the bar. Then one week, the man comes in and orders only two. He drinks them, then orders two more. The bartender sadly says, "Knowing your tradition, I'd just like to say that I'm sorry that one of your brothers died."
The man replies, "Oh, my brothers are fine -- I just quit drinking."
请问上段中的you're low与he sets up the guy's three beers中的low 与set up是何意思？

这段文章很有趣,非常喜欢。至於LOW 和 SET UP 在这里的解释也很明白。
"Sir, I know you like them cold, so you can start with one and I'll bring you a fresh one as soon as you're low."
"先生,我知道你喜欢冻啤酒,何不一枝快饮完我再送来一枝'新开的。'
所以这里low 的解释是快饮完,将饮尽的意思。

The bartender thinks it's a wonderful tradition, and every week he sets up the guy's three beers as soon as he enters in the bar.
这酒保认为这是他的一个奇妙的传统,所以每星期见他进来酒吧就为他准备了三枝啤酒.
所以这里的set up 是解作准备,设立,摆好的意思。