swims before it can fly, flies like a fat chicken, eats green leaves, has the stomach of a cow and has claws (爪) on its wings when young. They build their homes about 4.6m above the river, an important feature (特征) for the safety of the young. It is called the hoatzin.

In appearance, the birds of both sexes look very much alike with brown on the back and cream and red on the underside. The head is small, with a large set of feathers on the top, bright red eyes, and blue skin. Its nearest relatives are the common birds, cuckoos. Its most striking feature, though, is only found in the young.

Baby hoatzins have a claw on the leading edge of each wing and another at the end of each wing tip. Using these four claws, together with the beak (喙), they can climb about in the bushes, looking very much like primitive birds must have done. When the young hoatzins have learned to fly, they lose their claws.

During the drier months between December and March hoatzins fly about the forest in groups of 20 to 30 birds, but in April, when the rainy season begins, they collect together in smaller living units of two to seven birds for producing purposes.

63. What is the text mainly about? A. Hoatzins in dry and rainy seasons.

B. The relatives and enemies of hoatzins. C. Primitive birds and hoatzins of the Amazon. D. The appearance and living habits of hoatzins.

64. Young hoatzins are different from their parents in that . A. they look like young cuckoos B. they have claws on the wings C. they eat a lot like a cow D. they live on river banks

65. What can we infer about primitive birds from the text? A. They had claws to help them climb. B. They could fly long distances. C. They had four wings like hoatzins.

D. They had a head with long feathers on the top.

66. Why do hoatzins collect together in smaller groups when the rainy season comes? A. To find more food.

B. To protect themselves better. C. To keep themselves warm. D. To produce their young.

D

Science can't explain the power of pets, but many studies have shown that the company of pets can help lower blood pressure (血压) and raise chances of recovering from a heart attack, reduce loneliness and spread all-round good cheer.

Any owner will tall you how much joy a pet brings. For some, an animal provides more comfort than a husband/wife. A 2002 study by Karen Allen of the State University of New York measured stress (紧张) levels and blood pressure in people - half of them pet owners –while they performed 5 minutes of mental arithmetic (算术) or held a hand in ice water. Subjects completed the tasks alone, with a husband/wife, a close friend or with a pet. People with pets did it best. Those tested with their animal friends had smaller change in blood pressure and returned most quickly to baseline heart rates. With pets in the room, people also made fewer math mistakes than when doing in front of other companions. It seems people feel more relaxed (放松)around pets, says Allen, who thinks it may be because pets don't judge.

A study reported last fall suggests that having a pet dog not only raises your spirits but may also have an effect on your eating habits. Researchers at Northwestern Memorial Hospital spent a year studying 36 fat people and

their equally fat dogs on diet-and-exercise programs; a separate group of 56 people without pets were put on a diet program. On average, people lost about I1 pounds, or 5% of their body weight. Their dogs did even better, losing an average of 12 pounds, more than 15% of their body weight. Dog owners didn't lose any more weight than those without dogs but, say researchers, got more exercise overall-mostly with their dogs - and found it worth doing.

67. What does the text mainly discuss? A. What pets bring to their owners. B. How pets help people calm down. C. People's opinions of keeping pets. D. Pet's value in medical research.

68. We learn from the text that a person with heart disease has a better chance of getting well if .

A. he has a pet companion B. he has less stress of work C. he often does mental arithmetic D. he is taken care of by his family

69. According to Allen, why did the people do better with pets around when