What kind of cancer is the sixth-leading cause of cancer-related death worldwide？

听力原文： M: Did you know that astronauts have made commercial products in space？

W: No. I wasn't aware of that. What kind of products？

M: Tiny plastic beads.

W: Beads？ Do you mean to tell me that astronauts have nothing better to do than make jewelry beads in space？ It seems to me that they can make more useful things out there.

M: Oh ! But these plastic beads aren't for jewelry. They can be used for many scientific purposes, from conducting cancer research to calibrating microscopes.

W: That sounds better. But why make such objects in space rather than on earth？

M: Because earth’s gravitational pull affects the beads. The beads produces on earth are distorted not exactly round. The ones made in space are precise spheres.

What are the speakers mainly discussing？

A．Astronauts' clothing.

B．Products made in space.

C．Costume jewelry.

D．Problems in manufacturing.

听力原文：M: Did you know that astronauts have made commercial products in space？

W: No, I wasn't aware of that. What kind of products？

M: Tiny plastic beads with a little hole through it.

W: Tiny balls？ Do you mean to tell me that astronauts have nothing better to do than make jewelry beads in space？ It seems to me they could make more useful things out there.

M: Oh, but these little balls aren't for jewelry. They can be used for scientific purposes to conduct cancer research .

W: That sounds better, but why make such objects in space rather than on earth？

M: Because earth gravitational pull affects the beads. They produced on earth are distorted, not exactly tumid. The ones made in space are precisely round.

W: Sounds reasonable.

(23)

A．Astronauts' clothing.

B．Products made in space.

C．Costume jewelry.

D．Problems in manufacturing.

What Causes Cancer？

The question "What causes cancer？" has been asked for centuries. The short answer is: we still don't know. But a tremendous amount has added to our understanding in recent decades. One major change in the way researchers view cancer is that they now rarely think in terms of a single unitary cause. Rather, it appears that most cancers are caused by the interaction of several factors. In ninny cases, some or all of three factors may be involved: (1) viruses, (2) individual susceptibility, and (3) environmental irritants(刺激物). Another major change in our contemporary view of cancer is that it is now regarded as a premiere example of an environmental disease--that is, a disease in which environmental factors are often crucial to the disease process.

VIRUSES

A number of viruses have been identified that induce cancer in laboratory animals. What about humans？ As of the late 1970s, no virus had been shown conclusively to cause cancer in people. However, the scientific consensus was that it was probably only a matter of time before such a connection was proven.

Cancer, however, is not a communicable disease, like a cold or influenza. It is not "catching" in the ordinary sense of a word, and the mere presence of the suspect virus is apparently not enough, by it self, to produce the disease. It appears that the process may work something like this: A carcinogenic virus enters a cell and insinuates itself amidst the cell's genetic material. (Viruses and genes are structurally similar. ) The virus may then lie dormant(休眠的) for years, until it is triggered into action by some kind of environmental irritant, such as pollution or radiation. At that point, the reactivated virus causes changes in the genes, altering the host cell permanently and also altering all the cells produced by the division of the original cell. The genetic program of these new—and now cancerous-cell calls for tile unrestrained growth, dedifferentiation(分化), anaphase, and metastasis(转移)discussed earlier.

INDIVIDUAL SUSCEPIBILITY

Some people may be more prone to develop cancers than others, for several possible reasons.

Heredity is one. Resistance to cancer, or susceptibility to it, is a quality for which laboratory animals can be bred. So, presumably, heredity may play some role in humans as well. Statistical evidence, however, shows only a minor tendency for cancers to run in families. Indeed, for most cancers no such tendency can be demonstrated. Cancers of the breast, lung, thyroid, colon, and rectum do seem to cluster in families, at least to some degree. If your family has a history involving one of these cancers, you and your physician may want to be especially vigilant for signs of such cancer during your periodic physical examinations.

Some researchers have proposed that personality characteristics may render some people more vulnerable to cancer. According to this theory, people are more likely to develop cancer, and more likely to die from it, if they have rigid, authoritarian personality and suppressed inner conflicts about sexual and aggressive feelings. There have been many studies attempting to test this theory, and the results are thought-provoking. In one study, for example, doctors at the University of Rochester were able to predict with seventy-five percent accuracy whether women entering the hospital for a biopsy would have cancer or not, based on psychiatric interviews. However, this and many other studies linking cancer and psychological factors were performed on small samples. Well-controlled, large-scale, long-term studies are needed before the theory can be regarded as well established.

A third factor that might influence your susceptibility to cancer is the state of your immune system. When a person's immune system is weak, he or she has a heightened chance of developing ca

A．Y

B．N

C．NG

Amazing Rice

Rice comes in an astonishing array of sizes, shapes, and colors. Several distinct varieties of rice are commercially available, including long-grained Thai rice, medium-grain brown rice, short-grained arborio rice, Indian sticky rice, and sweet-smelling jasmine rice, to name just a few. Each kind of rice is especially suited for a particular style. of cooking, or a particular type of dish.

Regardless of the variety, all rice starts off as brown rice. The outer layer of the rice grain is called the bran, and this is what gives rice its distinctive brown color. When rice is milled, this outer bran layer is removed, leaving behind a white core that is essentially made up of simple carbohydrates. White rice, whatever its type, is simply rice that has had its bran removed.

The problem with white rice is that this stripped-off bran layer, the part that is removed during the milling process, is rich with nutrients, such as fiber, B vitamins, and minerals. This is why brown rice is nutritionally superior to white rice. For example, every cup of brown rice contains three and a half grams of fiber, while the same amount of white rice contains less than one gram. Increased fiber intake has been shown to reduce the risk of cancer and heart disease.

What is claimed about rice？

A．Most of the nutrients are in its outer layer.

B．It is the most commonly eaten grain in the world.

C．Every rice variety is sold as both white and brown rice.

D．Brown rice is not generally eaten in many parts of the world.

What is the substance in cigarettes that causes cancer？

A．Cigarette ashes.

B．Nicotine.

C．Tar.

D．Not mentioned here.

Which of the following is CORRECT about muscle-building？

A．It can help control stress, anxiety, and depression.

B．It takes time to increase one"s muscles" size and strength.

C．It reduces the risk of heart attack, cancer, and high blood pressure.

D．It can be classified as a kind of endurance exercise.

What did BBC online produce？

A．A list of doctors who specialize in cancer treatment.

B．A report of the increasing rate of cancer in the world.

C．A manual that teaches how to live a more healthy life.

D．A guide to the most common forms of cancer.

Red Meat Links to Higher Risk of Breast Cancer

Exercise and keeping a healthy weight are two things that doctors say might help women lower their risk of breast cancer.

Mothers may reduce their risk if they breastfeed for at least four months. For older women, hormone replacement therapy can lower the risk of some other diseases. But it has been found to increase the risk of breast cancer. So women should consider their choices carefully. The same may be said for diet.

New findings show that younger women who eat a lot of red meat have higher rates of breast cancers called hormone-receptor positive. The growth is fed by the levels of estrogen or another hormone, progesterone, in the body.

Researchers at Brigham Women's Hospital in Boston, Massachusetts, reported the findings as part of a health study of nurses. The researchers followed the health of more than 90,000 women from 1991 to 2003. Those who ate the most red meat ate more than one and one-half servings a day. A serving was defined as roughly 84 grams. Those who ate the least red meat ate less than three servings a week. This is what the study found about breast cancers that were hormone receptor-positive: The women who ate the most red meat were almost two times as likely to get them as the women who ate the least of it.

Eunyoung Cho, the lead author of the report, says more research is needed to know the reason for the link. But in the past, researchers have suggested that three things may play a part. One is the way meat is cooked or processed. Another is the use of growth hormones in cows. And the third is the kind of iron in red meat. The study appears in the Archives of Internal Medicine.

And now we have more to tell you about our subject -- resveratrol. We discussed a study in the United States that found that large amounts of this plant compound helped fat mice live longer. The mice were fed much more resveratrol than people could get from red wine, one of the foods that contains it.

Now, scientists in France say resveratrol also improves muscle performance -- again, at least in mice. They were able to run two times as far in laboratory treadmill tests4 as mice normally could. The study at the Institute of Genetics and Molecular and Cellular Biologys appeared in the journal Cell.

Breastfeeding helps women prevent the development of breast cancer to a certain degree.

A．Right

B．Wrong

C．Not mentioned

lants, where exists a great reluctance 【M1】______ to accept viruses as been of importance in human cancer. Basic 【M2】______ biological phenomena generally does not differ strikingly as 【M3】______ one goes from one species to other. It should be recognized that 【M4】______ cancer is a biological problem and not a problem that is unique for man. Cancer originates when a normal cell suddenly becomes a cancer cell which multiplies widely and with apparent restraint. 【M5】______ Cancer cells originate in many different kinds of cell, but the cancer cell usually continues to carry certain traits of the cell of origin. The transformation of a normal cell to a cancer cell may 【M6】______ have more than one kind of cause, but theres good reason to consider the relationships exist between viruses and cancer. Since theres no evidence which human cancer, as generally 【M7】______ experienced, is infectious, many person believe that because 【M8】______ viruses are infectious agents, they can possibly be of important in 【M9】______ human cancer. Furthermore, viruses and examples are known in which a virus never kills its host can mutate to form. a new strain 【M10】______ of virus that always kills its host. It does not seem unreasonable to assume that an innocuous latent virus might mutate to form. a strain that causes cancer.

【M1】

ther cigarettes really do cause lung cancer, what causes malnutrition, the decay of cities, or the decay of teeth. We are equally interested in effects: what is the effect of sculpture or lead in the atmosphere, of oil spills and raw sewage in rivers and the sea, of staying up late on the night before an examination？

Causal reasoning may go from cause to effect or from effect to cause. Either way, we reason from what we know to what we want to find out. Sometimes we reason from an effect to a cause and then on to another effect. Thus, if we reason that because the lights have gone out, the refrigerator won't work, we first relate the effect (lights out) to the cause (power off) and then relate that cause to another effect (refrigerator not working). This kind of reasoning is called, for short, effect to effect. It is quite common to reason through an extensive chain of causal relations. When the lights go out we might reason in the following causal chain: lights out — power off — refrigerator not working — temperature will rise — milk will sour. In other words, we diagnose a succession of effects from the power failure, each becoming the cause of the next.

Causes are classified as necessary, sufficient, or contributory. A necessary cause is one which must be present for the effect to occur, as combustion is necessary to drive a gasoline engine. A sufficient cause is one which can produce an effect unaided, though there may be more than one sufficient cause: a dead battery is enough to keep a car from starting, but faulty spark plugs, or an empty gas tank will have the same effect. A contributory cause is one which helps to produce an effect but cannot do so by itself, as running through a red light may help cause an accident, though other factors — pedestrians or other cars in the intersection — must also be present.

In establishing or refuting a causal relation it is usually necessary to show the process by which the alleged cause produces the effect. Such an explanation is called a causal process.

What the author discussed in the previous section is most probably about ______.

A．relationships between causes and results

B．classification of reasoning

C．some other common types of reasoning

D．some special type of reasoning