Farley worked for the Canadian government. One day, he was ___   to learn more about wolves. Do wolves kill lots of caribou(北美驯鹿)? Do they kill people?

They gave him lots of food and clothes and guns. Then they put him on a plane and took him to ____  . The plane put him down and went away. There were no houses or people in this place. But there were lots of animals and lots of wolves.

People tell terrible stories about wolves. They say wolves like to kill and eat people. Farley remembered these stories, and he was ____. He had his gun with him___ .

Then one day, he saw a group of wolves. There was a mother wolf with four baby wolves. A father wolf and another young wolf lived with them.

Farley watched these wolves every day. The mother was a very ____ mother. She gave milk to her babies. She gave them lessons about life. They learned how to ____ food. The father wolf got food for the mother. The young wolf ____ the children. They were a nice, happy family—wolf family! Farley did not need his ____ any more. In a short time, he got on well with the family. Farley watched them for five months. He learned that many stories about the wolves were ____. Wolves do not eat people, and they do not eat many large animals. And he also learned bad things about men. It was men who killed many caribou and wolves.

　Later, Farley wrote a book about wolves. He wanted people to ____ them and not to kill them.

下列各项关于采购战略的表述，正确的有（）。

A.采购组合是质量、数量、价格和种类

B.多货源策略缺点是供应商的承诺较低

C.单一货源策略便于信息的保密

D.多货源策略可以有效使用外部技术