textiles. Because when humans stopped hunting and started raising animals, it was their first step from a wild life to a civilized one. Sheep became a convenience store for the new lifestyle of our ancestor during the Stone Age, a walking food supply that required little care. Sheep provided all - meat and milk for food, skin and bones for clothing, shelters and tools.

　　Some sheep were suitable to roast while others were to produce wool, as sheep fit for eating do not necessarily have high­quality wool. Early wild species of sheep had long outer hair protecting their short wool undercoats. It was this underlayer that was highly suitable for textile use, so they were selectively bred into modern sheep.

　　Great empires were built on the backs of sheep and their wool. Around 1800 BC, the civilization of Babylonia was famous for its wool. After the Romans conquered Spain, they developed a new breed (品种) that would come to be known as Spanish Merino, with the whitest, finest wool ever known. Today, the Merino is the most highly regarded breed in the world.

　　The Chinese held onto the secret of silk for thousands of years before Europeans even got an idea about how to put two threads together. With wool, they_seem_to_have_got_their_revenge.

　　4．What do we know about raising sheep in the Stone Age?

　　A．People made great efforts to raise sheep.

　　B．People exchanged sheep for what they needed.

　　C．Sheep led to the boom of ancient society.

　　D．Sheep met many basic needs of ancient people.

　　解析：选D　细节理解题。根据第二段的"Sheep became a convenience store for the new lifestyle ... meat and milk for food, skin and bones for clothing, shelters and tools"可知，羊的肉和奶可作为食物，皮可作为衣服和遮蔽物，而骨头可用于制作各种工具，即羊满足了古人的许多基本需求，故选D。

　　5．What is the main idea of Paragraph 3?

　　A．Economic value of sheep.

　　B．Features of sheep breeds.

　　C．Choice of suitable sheep breeds.

　　D．Development of the wool industry.

解析：选C　段落大意题。根据第三段的内容可知，本段主要介绍了不是所有的羊都适合用于羊毛编织，故人们选择了合适的品种饲养。故选C。