,

lactate

. Our next question is: do you know what that means? To lactate means to produce milk. Cows lactate for up to ten months.

In milk, fat rises to the top. But some people do not like to drink milk that way. So there is a process that reduces the size of the fat

particles

and mixes them all through the milk. This process has a name -- a long name. What is it? It's called

homogenization

.

Still with us? OK, another question. Milk can be made into cheese. Some people like cheese made with milk from a sheep. What do you call a female sheep? The answer: a ewe, spelled E-W-E.

Male sheep have their own name. A male sheep is a -- what? A ram.

Rams and ewes produce lambs. A lamb is a sheep less than a year old. But what do you call the meat from a sheep over a year old? Then we call it mutton.

Age also

plays a part

in terms for horses. For example, a

mare

is generally a female three years or older. But what do you call a female horse under three? The answer: a filly. And for extra credit: do you know the name for a male horse under four? A colt.

If you want to take this quiz again, you can find it at voaspecialenglish.com. And that’s the VOA Special English Agriculture Report.

vocabulary quiz ：词汇测试

play a part: 装腔骗人；扮演角色；在 … 中起一份作用

perennial [p ə 'reni ə l]