下列哪些方面是孔内事故的预防（）A、钻进中因故停钻时，应及时设法将钻具提出孔口或安全

关于张力性气胸，哪项错误（）

A.常继发于慢性阻塞性肺疾病或肺结核

B.胸腔压力超过大气压

C.可使纵隔严重移位，影响心脏血液回流

D.必须紧急抽气减压

E.一般抽气减压后，胸腔内压力不再上升

The word "preserved" in line 8 is closest in meaning to

A．( confused with others

B．( gradually weakened

C．( protected from destruction

D．( lost permanently

阅读理解。

     Recently, many of America's biggest zoos have decided to close down their elephant exhibits.

A new study shows that elephants live better in the wild.

     Researchers studies 4,500 elephants in European zoos and compared them with elephants living

in wild. They found that wild elephants are healthier, live longer and reproduce(繁殖) more than those

kept in zoos.

     Many animals live longer in zoos than those who live in the wild. In zoos, they are not worried

about some animals that may attack them at any time when in the wild. There's always plenty to eat.

And they are cured when sickness strikes. But when it comes to elephants, the situation is different.

     The researchers said that zoos do not offer enough space for elephants to walk about as much as

30 miles a day. Too little exercise and too much food are causing zoo elephants to put on extra pounds.

The weight gain can lead to heart disease and other health problems. Even the baby elephants born in

zoos are heavier than those born in the wild.

     Bringing Asian and African elephants together in zoos has also caused problems. A disease that is

not dangerous for African elephants has spread to Asian elephants, and is harming them. " Zoos have

accidentally created this," says Mason. "It's killing Asian adult elephants."

    Exerts point out that keeping elephants in zoos isn't a problem for the animals only; it's also quite

costly for humans. In the last 10 years, zoos have spent about $500 million on caged space for about

250 animals.

1. Compared with wild elephants, elephants in zoos ______.

A. live longer  

B. are heavier  

C. are healthier  

D. reproduce more

2. The fourth paragraph mainly tells us that ______.

A. baby elephants are difficult to live in zoos

B. elephants walk as long as miles a day

C. little room to wander leads to problems for elephants

D. too much food in zoos leads to heart disease for elephants

3. What can we learn from the passage?

A. Asian elephants are more easily attacked by diseases than African elephants.

B. The diseases of zoo elephants are caused by being overweight.

C. Zoos free the elephants because of the cost of keeping them.

D. Elephants live better in the wild than in zoos.

4. The passage is probably taken from _____.

A. the zoo rules        

B. a guide book  

C. a healthy program    

D. a science magazine

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