题目内容：

    Being able to tell human faces apart is a skill that almost every person has, although some are far better at it than others. But a new study out from the journal Scientific Reports says that this is not just a skill that humans possess. Even fish can do it.

Following up on research studying different species’ abilities to recognize human faces (sheep, dogs, cows, horses, and-birds have all been tried), the researchers from the University of Oxford and the University of Queensland decided to pick an animal that does not have an evolved neocortex, the part of the brain that processes sight and sounds, and does not have a close relationship with humans. That way, there would be no reason why these test subjects would have a past history of identifying human faces. So they picked the archerfish, a reef fish variety that shoots water into the air to knock its prey out of the sky. They used this adaptation to have the fish spray water at a face on a monitor hanging over their tanks for a reward. Most of the fish were able to pick out their learned face, even when colors were taken away or methods were used to make the face shapes unclear.

This study gives more backing to the hypothesis that differentiating between faces is not just a skill that big -brained organisms are born with. It is possible that a good portion of recognizing faces is learned over time. The development of the neocortex may contribute only to quickly process a large number of faces in varying situations. But more work needs to be conducted to find a deeper link to this possible learned behavior. The sample size of this study was very small—only eight fish were used altogether. Also, the faces displayed on the monitor were only white, female faces from a German database, shown in a frontal view, with no expressions. Other animal trials have shown that some species, like pigeons, respond more to differing angles and varied expressions.

1.What is the purpose of this passage?

A.To improve a scientific experiment design. B.To present the differences between species.

C.To clarify how animals tell human faces apart. D.To show animals can recognize human faces.

2.Why were the archerfish chosen as test subjects?

A.They are cleverer than other species. B.They have sharp vision and hearing.

C.They aren’t closely related to humans. D.They have a past history of identifying human faces.

3.What is the author’s attitude toward the study?

A.Cautious. B.Negative.

C.Consistent. D.Sympathetic.

4.Which of the following is suggested for similar studies in the future?

A.Including more test subjects. B.Enlarging the human faces.

C.Employing more male researchers. D.Using black-and-white pictures.