Q: What's the difference between a monkey and a flea?
问题：猴子和跳蚤的区别是什么？
A: A monkey can have fleas, but a flea can't have monkeys.
答案：猴子可以有跳蚤，跳蚤却不能在猴子身上。

1.between…and…
问题是问两者之间有什么区别，所以用between…and。
如果是问三者及三者以上，一般要用among这个单词了。
今天就重点来说说between…and…
(1)连接两者,表示在…之间，如：
I’ll phone you between lunch and three o'clock. 我将在午餐后三点钟以前给你打电话。
He felt something between laughter and anger. 他既觉得好笑，又感到气愤。

(2) 由于……和……(表示原因)。如：
Between the noise outside and lack of sleep, he couldn't concentrate. 由于外面的噪音加上睡眠不足，他无法专心。
注：between...and 不仅可连接两者，也可连接三者。如：
Luxemburg lies between France, Germany and Belgium. 卢森堡位于法国、德国和比利时之间。
Between cooking, writing and running the farm he was kept very busy. 他又是做饭，又是写作，还要打理农场，忙得不可开交。

(3) 用于习语：between ourselves [you and me] 仅你我知道的秘密。如：
Between ourselves, I don’t think he will live much longer. 咱们私下说说，他活不久了。
Between you and me, he’s not very reliable. 这是只有你我之间才说，他不是很可靠。

2.flea
作名词跳蚤，蚤目的昆虫；生蚤的动物
复数：fleas
flea market：跳蚤市场。