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A．overestimated ... a minor
B．discounted ... a vestigial
C．valued ... a major
D．ignored ... a pivotal
E．studied ... an inaccessible
答案
更多“Although scientists have long ______ the human appendix as ______ organ, there is a growin”相关的问题
第1题
第2题
New Technique Promises Earlier Cancer Detection
A new technique could revolutionize the early detection of cancer, giving sufferers a greater chance of beating the disease, American scientists said. Researchers at the Massachusetts Institute of Technology have devised a novel method of(51)changes in the nucleus of cells in the earliest stages of the disease. "More than 85 percent of all cancers originate in the epithelium (上皮) that lines the internal surfaces of organs(52)the body. Although these are treatable(53)they are diagnosed in one of the preventable stages, early body damages are almost(54)to detect," said scientist Feld. "We present a new optical-probe (光学探子) technique based on light-scattering spectroscopy (分光镜检查) that is able(55)detect pre-cancerous and early cancerous cells in cell-rich epithelia," he added in a statement.
The new technique relies on the fact(56)cell nuclei change in the early stages of cancer and the differences scatter light in a characteristic way. Until now the changes were only detectable(57)a biopsy (活检) was taken, the scientists said. The new technique,(58)in the science journal Nature, can be used in conjunction with a routine cancer screening and surveillance technique which uses an endoscope (内窥镜)--a flexible optical probe(59)with cameras which is inserted into a cavity in the body--to check(60)cancers.
The scientists said they(61)their new technique in four different organs during routine endoscopic cancer screening. The tip of the optical probe was brought into contact with the tissue to be tested and the scattering of light was recorded without the need for any tissue to be(62), the scientists said. "Our results show that light-scattering spectroscopy has the potential to detect pre-cancerous body damages and pre-invasive cancers throughout the body. This technique should(63)improve the efficiency of cancer screening and surveillance," the scientists said. Cancer is one of the biggest(64)in industrialized countries.(65)to figures from the World Health Organization, 10 million people were diagnosed with the disease worldwide in 1997 and six million died.
A．stopping
B．accelerating
C．detecting
D．delaying
第3题
听力原文： Colds have always been a nuisance, and people have tried many strange ways to cure them, However, none have worked. one Roman historian even recommended kissing the nose of a hairy mouse (29) ! But up till now we are only a little closer to finding a cure for it.
Scientists have discovered that a cold is not caused by a single virus, but by many. They have proved that people under stress are more likely to catch colds, although why this happens is still unknown (30) . Experiments also showed that women suffer more colds than men. But again, scientists are unable to explain why this is so.
Another experiment proved that getting cold does not cause colds. For this experiment, one group of human volunteers were showered with water and then made to stand in a windy corridor. Another group remained dry and inside a heated room. While you might expect people in the first group to catch colds more easily, they didn't.
one other thing that we now know is that colds are spread by water vapor from breath. This would explain why colds are more common in the winter than at other times: people spend more time indoors closer to other people, and also away from flesh air (31) .
(30)
A．Keeping warm and dry.
B．Drinking a lot of liquid.
C．Living close to the hospital.
D．Kissing the nose of an animal.
第4题
THAN WHICH CONTRIBUTE A. THESE NUTRIENTS CAN (56)______TO THE BREEDING OF THE ORGANISMS
B. MORE (57)______2, 600 SQUARE KILOMETERS
C. (58)______CARRY POISONOUS SUBSTANCES THE TERM "RED TIDE" APPLIES TO THE DISCOLORATION OF WATER THAT SOMETIMES OCCURS IN CERTAIN AREAS OF THE OCEAN OR SEA. ALTHOUGH THE COLOR IS OFTEN RED, IT MAY ALSO BE SHADES OF BROWN OR YELLOW. THE WORLD BOOK ENCYCLOPEDIA REPORTS THAT "THE DISCOLORED AREAS MAY RANGE FROM LESS THAN A FEW SQUARE YARDS TO(59)______." WHAT CAUSES SUCH DISCOLORATION？ RED TIDES ARE GENERALLY CAUSED BY SEVERAL SPECIES OF SINGLE-CELLED ORGANISMS. THESE TINY ORGANISMS HAVE HAIR-LIKE PROJECTIONS WHICH THEY USE TO PROPEL THEMSELVES IN WATER. THERE ARE ABOUT 2,000 VARIETIES OF THESE ORGANISMS, 30 OF (60)______ THESE MINUTE ORGANISMS USUALLY STAY IN WARM WATERS WITH HIGH CONTENT OF SALT. A RED TIDE OCCURS WHEN THERE IS A SUDDEN AND RAPID BLOOM OF THESE ORGANISMS. THE CONCENTRATION OF THESE ORGANISMS MAY SWELL TO 50, 000, 000 PER QUART OF WATER! ALTHOUGH SCIENTISTS DO NOT FULLY UNDERSTAND WHY THIS HAPPENS. IT IS KNOWN THAT THESE ORGANISMS ACCUMULATE WHEN CERTAIN CONDITIONS SIMULTANEOUSLY AFFECT THE WATER. THESE INCLUDE ABNORMAL WEATHER, OPTIMUM TEMPERATURES, AN OVERSUPPLY OF NUTRIENTS IN THE WATER, A GENEROUS AMOUNT OF SUNLIGHT, AND FAVORABLE WATER CURRENTS. WHEN A HEAVY RAINFALL OCCURS, MINERALS AND OTHER NUTRIENTS ARE SOMETIMES WASHED FROM THE LAND INTO COASTAL WATER. (61)______. THE RESULT？ RED TIDES!
第5题
A laboratory experiment conducted last fall suggests it may someday be possible. For the first time ever, scientists made exact copies, or clones(克隆), of a human embryo.
Although the embryos grew for only six days, cloned embryos could theoretically be implanted in a woman's womb(子宫)and develop into normal babies. Or they could be frozen and implanted years later.
The scientists developed their cloning technique to make it easier for childless couples to have babies by in vitro(在体外的)fertilization. In this procedure, sperm(精子) from the man fertilizes an egg from the woman in a laboratory dish.
In most case, doctors must try implanting several embryos before one stays in the womb. Cloned embryos would give them many more embryos to implant.
But the technique could also be used for other purposes. Parents might freeze embryos cloned from their children so that they could be replaced if any of them died. The clones would also be ideal donors if the children needed organ transplants.
Another possibility: Childless couples could go to a bank of frozen embryos and choose a child just like one who's already living. Some people are concerned that these couples might pick only beautiful, successful children.
The ethical dilemmas(困境)of cloning have not yet been discussed fully because the public assumed it was a long way off. Many people are calling for(要求，提倡)controls on cloning immediately before the practice is abused. What do you think？
In an experiment conducted last autumn, scientists made exact copies of a human embryo for the first time.
A. Right
B. Wrong
C. Not mentioned
第6题
请根据短文内容，回答题。
Black Holes
Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers(天文学家) think that at the center of a black hole there is a single point in space with infinite (无限的 ) density (稠密 ) . This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point.＜br＞
Anything that crosses the black hole is pulled in by its great gravity.＜br＞
Although black holes do exist, they are difficult to observe. These are the reasons.＜br＞
No light or anything else comes out of black holes. As a result, they are invisible to a telescope.＜br＞
In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon (视界) only 18 miles across.＜br＞
The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion (万亿) miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.＜br＞
In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are still answers to be found, however, so black holes remain one of the mysteries of the universe.＜
Black holes are part of space. 查看材料
A.Right
B.Wrong
C.Not mentioned
第7题
Using HIV Virus to Cure Cancer
Scientists are planning to use human immunodeficiency (免疫缺陷) virus (HIV), one of mankind's most feared viruses, as a carrier of genes which can fight cancer and a range of diseases that cannot be cured. The experts say HIV has an almost perfect ability to avoid the body's immune (免疫的) defenses, making it ideal for carrying replacement genes into patients' bodies, according to the Observer.
A team at the California-based Salk Institute, one of the world's leading research centers on biological sciences, has created a special new breed of HIV and has started negotiations with the U.S. Food and Drug Administration (FDA) to begin clinical gene therapy (治疗) trials this year. The first trials are expected to involve patients suffering from cancers that cannot be cured by surgery although project leader Professor Inder Verma said the HIV technique would have "far wider applications".
The plan remains very likely to cause controversy since it involves making use of a virus which has caused more than 22 million deaths around the world in the past two decades. Verma said that the idea of using HIV for a beneficial purpose was "shocking" but the fierce nature of HIV had disappeared by having all six of the potentially deadly genes removed.
Illnesses such as various cancers are caused when a gene in a patient's body fails to work properly. In the past two years, breakthroughs in genetics (遗传学) have led gene therapy scientists to try and replace the genes that de not function normally.
Unfortunately, the body's immune defenses have been known to attack the modified genes and make them lose their effects before they can start their task and progress in the field has been held up by the lack of a suitable carrier.
The HIV virus has the ability to escape from, and then destroy, the immune defense cells designed to protect our bodies and this makes it attractive to scientists as a way of secretly conveying replacement genes into patients' bodies.
FDA has approved the plan of using HIV to cure cancer in humans.
A．Right
B．Wrong
C．Not mentioned
第8题
根据下面材料，回答题。
Black Holes
Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers(天文学家) think that at the center of a black hole there is a single point in space with infinite (无限的) density (稠密). This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point.
Anything that crosses the black hole is pulled in by its great gravity.
Although black holes do exist, they are difficult to observe. These are the reasons.
？ No light or anything else comes out of black holes. As a result, they are invisible to a telescope.
？ In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon (视界) only 18 miles across.
？ The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion (万亿) miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.
In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are still answers to be found, however, so black holes remain one of the mysteries of the universe.
Black holes are part of space. 查看材料
A.Right
B.Wrong
C.Not mentioned
第9题
Black Holes
Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers (天文学家)think that at the center of a black hole there is a single point in space with infinite (无限的)density (稠密). This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point. Anything that crosses the black hole is pulled in by its great gravity.
Although black holes do exist, they are difficult to observe. These are the reasons.
-- No light or anything else comes out of black holes. As a result, they are invisible to a telescope.
-- In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon(视界)only 18 miles across.
-- The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion(万亿)miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.
In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are still answers to be found, however, so black holes remain one of the mysteries of the universe.
Black holes are part of space.
A．Right
B．Wrong
C．Not mentioned
