以实际运行中过热器爆管的情况来看，大多数都不是由于管子长期过热超温而引起的。

People have known since ancient times that aspirin（阿司匹林） reduces pain and lowers high body temperature. But that is not all the drug can do. In recent years, it has been used in other ways, too. Small amounts may help prevent a stroke or heart attack. One recent study showed that some people who took two aspirin pills a day had lower rates of colorectal cancer. And, some researchers say aspirin may help patients with colon cancer live longer. So, how did aspirin become so important? The story begins with a willow（柳树）．

2, 000 years ago, the Greek doctor Hippocrates advised his patients to chew on the bark and leaves of the willow. The tree contains a chemical called salicin. In the 1800s, researchers discovered how to make salicylic acid from the chemical. In 1897, a chemist named Felix Hoffmann at Friedrich Bayer and Company in Germany created acetyl salicylic acid. Later, it became the active substance in a medicine that Bayer called aspirin. The "a" came from acetyl. The "spir" came from the spirea plant, which also produces salicin. And the "in" ? That is a common way to end medicine names.

In 1982, a British scientist shared the Nobel Prize in Medicine in part for discovering how aspirin works. Sir John Vane found that aspirin prevents the body from making the natural substances called prostaglandins. Prostaglandins have several effects on the body. Some cause pain and swelling（肿）． Prostaglandins also make the heart, kidneys(肾) and blood vessels work well. So there is a problem. Aspirin works against all prostaglandins, good and bad. It can also harm the inside of the stomach, and sometimes it can cause bleeding.

But a British study released in 2009 suggested that taking another drug with a small amount of aspirin may help reduce the risk of bleeding. If this proves true, it would help thousands of people who are seeking to prevent life-threatening conditions.

小题1: The writer wrote this passage to______.

A．tell us the harm of aspirin

B．help us know aspirin better

C．explain why aspirin is useful

D．prove that aspirin is a good medicine小题2:What do we learn about aspirin from Paragraph 1?

A．It is not used until recent years.

B．Using it for a long time may lead to cancer.

C．It is very dangerous if it is used in the wrong way,

D．It has gained important new uses in recent years.小题3:When was the acetyl salicylic acid created?

A．about 2,000 years ago.

B．In the early 1800s.

C．In the late 1800s

D．In recent years小题4:What is waiting to be solved according to the last paragraph?

A．The bleeding caused by taking aspirin.

B．How to reduce the risk of getting colorectal cancer.

C．How to help patients with colon cancer live longer

D．The problem of low body temperature caused by taking aspirin

被誉为“茶中之冠”的是（）。

A.武夷大红袍

B.洞庭碧螺春

C.西湖龙井

D.云南普洱茶

CT检查中：①钙化②囊液③脂肪④新鲜出血，密度从高到低，依次排列为（）

A.①②③④

B.①③②④

C.①④②③

D.②③④①

E.④①②③

网中任意一个结点的故障引起全网故障的网络是（）

A、环形网

B、星型网

C、树型网

D、总线型网

George Williams, one of Scottsdale’s last remaining cowboys, has been raising horses and cattle on his 120 acres for 20 years. The cattle go to the slaughterhouse, the horses to rodeos. But Mr. Williams is stomping mad. His problems began last year when dishonest neighbours started to steal his cattle. Then other neighbours, most of them newcomers, took offence at his horses roaming on their properties.

Such grumbles are common in Arizona. The most recent Department of Agriculture census shows that 1 213 of Arizona’s 8 507 farms closed down between 1997 and 2002. Many cattlemen are moving out to remoter parts of the state.

Doc Lane is an executive at the Arizona Cattlemen’s Association, a trade group. He says Arizona’s larger ranch owners are making decent profits from selling. It is the smaller players who are the victims of rising land values, higher mortgages and stiffer city council rules. What happens all too often is that people move in next to a farm because they think the land pretty. But soon they start complaining to the council. In Mr. Williams’s case it was the horses that annoyed them. Other newcomers don’t like the noise, the pesticides and the smell of manure.

Locals worry about the precious, dwindling cowboy culture. Arizona’s tourism boards like to promote a steady interest in all things about cowboy and western. Last year more British and German tourists came than usual, and many of them were looking precisely for that. Arizona’s Dude Ranch Association fills its $ 350-a-night luxury ranches most of the year; roughly a third of the guests are European.

Many of the ranchers themselves see all this tourism as a cheeky attempt to commercialise a real and vanishing culture. In Prescott, estate agents promote "American Ranch-style" homes with posters of horse riders. On the other side of the street is Whiskey Row, a famous strip of historic cowboy bars. But in Matt’s Saloon on Saturday night, real cattlemen could not be found.

Farm folk like Mr. Knox and Mr. Williams are weighing up their options. Many will migrate to remoter places where land is cheaper and not crowded with city people. Younger ones take on side-jobs as contractors and are cattle-hands part-time. Older cowboys aren’t sure what to do.

What is the author’s attitude towards cattlemen（）

A. Combative

B. Contemptuous

C.Compassionate

D. Compromising