An amusement park in France has come up with an unusual way of picking up litter. They have trained crows (乌鸦) to pick up small pieces of litter in order to earn a reward (奖励).

Puy du Fou is the second most popular theme park in France. The park puts on historical shows about different periods of time. For example, they have had shows about the time of the Vikings and the time of the Romans.

For some of the shows, Puy du Fou uses trained birds. At times as many as 300 birds fly at the same time. One day Christophe Gaborit, who works with the birds, started wondering if birds could be trained to pick up litter. Several years ago, Mr. Gaborit began working with two rooks. Rooks are a kind of crow. They are known for being clever and for working well with humans.

Mr. Gaborit created a special box to train his crows. The box had two drawers. The crows were trained to put a piece of litter into one drawer. When they did that. Mr. Gaborit would slide a board to show a small treat for the crow in the other drawer.

Once the crows learned that they could get food by putting litter in the box, they became good at flying around and picking up small pieces of litter. They always seemed to want more food. Mr. Gaborit said that sometimes the rooks would try to trick him by bringing back something that was not litter, like a piece of wood.

This year, Mr. Gaborit and Puy du Fou decided that they should train more crows, so that they could help clean the park. Nicolas de Villiers, who ran the park, said that one of their reasons for doing this was to show “that nature itself can teach us to take care of the environment”.

【小题1】Why do the rooks pick up litter?

A．To earn a treat.	B．To gain their master’s love.
C．To exchange for money.	D．To protect the environment.

【小题2】How did Mr. Gaborit train his two crows?

A．By teaching them the meaning.	B．By using a special box.
C．By showing them historical shows.	D．By punishing wrong behaviors.

【小题3】What can we infer from paragraph 5?

A．The rooks are very smart.

B．Wood is some kind of litter.

C．The rooks fly around to look for food.

D．Mr. Gaborit is strict with the trained birds.

【小题4】Where is the text most likely from?

A．A school textbook.	B．A government report.
C．A nature magazine.	D．A research paper.