单选题Adaptation of Living Things Certain animals and plants develop characteristics that help them cope with their environment better than others of their kind. This natural biological process is called adaptation. Among the superior characteristics developed through adaptation are those that may help in getting food or shelter, in providing protection, and in producing and protecting the young. That results in the evolution of more and more organisms (微生物) that are better fitted to their environments. Each living thing is adapted to its way of life in a general way, but each is adapted especially to its own distinct class. A plant, for example, depends upon its roots to fix itself firmly and to absorb water and inorganic (无机的) chemicals. It depends upon its green leaves for using the sun"s energy to make food from inorganic chemicals. These are general adaptations, common to most plants. In addition, there are special adaptations that only certain kinds of plants have. Many animals have adaptations that help them escape from their enemies. Some insects are hidden by their body color or shape, and many look like a leaf or a little branch. The coats of deer are colored to mix with the surroundings. Many animals have the ability to remain completely still when an enemy is near. Organisms have a great variety of ways of adapting. They may adapt in their structure, function, and genetics; in their development and production of the young; and in other respects. An organism may create its own environment, as do warm-blooded mammals (哺乳动物), which have the ability to adjust body heat exactly to maintain their ideal temperature despite changing weather. Usually adaptations are an advantage, but sometimes an organism is so well adapted to a particular environment that, if conditions change, it finds it difficult or impossible to readapt to the new conditions.

单选题 下面有3篇短文，每篇短文后有5道题。请根据短文内容，为每题确定1个最佳选项。{{B}}第一篇{{/B}} Radiation Effect Space is a dangerous place, not only because of meteors (流星)but also because of rays from the sun and other stars. The atmosphere again acts as our protective blanket on earth light, gets through, and this is essential for plants to make the food that we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air from outer space, but enormous quantities of radiation from the sun are screened off. As soon as men leave the atmosphere they are exposed to this radiation, but their spacesuits or the walls of their spacecrafts, if they are inside, do prevent a lot of radiation damage. Radiation is the greatest known danger to explorers in space. The unit of radiation is called "rem" (“雷姆”). Scientists have reason to think that a man can put up with far more radiation than 0.1 rem without being damaged, the figure of 60 reins has been agreed on. The trouble is that it is extremely difficult to be sure about radiation damage-a person may feel perfectly well, but the cells of his or her sex organs may be damaged ,and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren. Missions of the Apollo flights have had to cross belts of high radiation and, during the outward and return journeys, the Apollo crew accumulated a larger amount of reins. So far, no dangerous amounts of radiation have been reported, but the Apollo missions have been quite short. We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere, working in a space laboratory. Drugs might help to decrease the damage clone by radiation ,but no really effective ones have been found so far.

单选题He demolished my arguments in minutes.

单选题Who is the head of this delegation?

单选题The food is {{U}}inadequate{{/U}} for ten people.

单选题He was {{U}}weary{{/U}} of the constant battle between them. A. fond B. proud C. tired D. afraid

单选题Ants Have Big Impact on Environment as "Ecosystem Engineers" Research by the University of Exeter has revealed that ants have a big impact on their local environment as a result of their activity as "ecosystem engineers" and predators. The study, published in the Journal of Animal Ecology, found that ants have two distinct effects on their local environment. Firstly, through moving of soil by nest building activity and by collecting food they affect the level of nutrients in the soil. This can indirectly impact the local populations of many animal groups, from decomposers to species much higher up the food chain. Secondly, they prey on a wide range of other animals, including larger prey which can be attacked by vast numbers of ant workers. Dirk Sanders, an author of the study from the university"s Centre for Ecology and Conservation, said: "Ants are very effective predators which thrive in huge numbers. They"re also very territorial and very aggressive, defending their resources and territory against other predators. All of this means they have a strong influence on their surrounding area." "In this research, we studied for the first time how big this impact is and the subtleties of it. What we found is that despite being predators, their presence can also lead to an increase in density and diversity of other animal groups4. They genuinely play a key role in the local environment, having a big influence on the grassland food web," Sanders said. The study, carried out in Germany, studied the impact of the presence of different combinations and densities of black garden ants and common red ants, both species which can be found across Europe, including in the UK. It found that a low density of ants in an area increased the diversity and density of other animals in the local area, particularly the density of herbivores and decomposers. At higher densities ants had no or the opposite effect, showing that predation is counteracting the positive influence. Dr Frank van Veen, another author on the study, said. "What we find is that the impact of ants on soil nutrient levels has a positive effect on animal groups at low levels, but as the number of ants increases, their predatory impacts have the bigger effect — thereby counteracting the positive influence via ecosystem engineering." Ants are important components of ecosystems not only because they constitute a great part of the animal biomass but also because they act as ecosystem engineers. Ant biodiversity6is incredibly high and these organisms are highly responsive to human impact, which obviously reduces its richness. However, it is not clear how such disturbance damages the maintenance of ant services to the ecosystem. Ants are important in below ground processes through the alteration of the physical and chemical environment and through their effects on plants, microorganisms, and other soil organisms.

单选题UWhile/U we don't agree, we continue to be friends.

单选题Argument among the speakers at the conference Uis bordering/U on violence.

单选题Lunge cancer, hypertension, heart disease, birth defects—we are all too familiar with the danger of smoking. But add to that list a frightening new concern. Mental illness. According to some controversial new findings, if smoking does not kill you, it may, quite literally, drive you to despair. The tobacco industry openly pushes its product as something to lift your mood and soothe anxiety. But the short-term feel-good effect may mask the truth :that smoking may women or even trigger anxiety disorders, panic attacks and depression ,perhaps even schizophrenia (精神分裂症) What is the main idea of the two paragraphs?A. Smoking causes great dangers to the body.B. Smoking is a good way to soothe anxiety.C. Smoking probably leads to mental illness.D. Smoking does not kill smokers.

单选题The painter Les Quinones, whose graffiti art has been exhibited in New York galleries, has also painted outdoor murals in various Manhattan neighborhoods. A. sold B. shown C. kept D. praised

单选题 When Fear Takes Control of the Mind A panic attack is a sudden feeling of terror. Usually it does not last long, but it may feel like forever. The cause can be something as normally uneventful as driving over a bridge or flying in an airplane. And it can happen even if the person has driven over many bridges or flown many times before. A fast heartbeat. Sweaty hands. Difficult breathing. A dizzy feeling. At first a person may have no idea what is wrong. But these can all be signs of what is known as panic disorder. The first appearance usually is between the ages of 18 and 25. In some cases it develops after a tragedy, like the death of a loved one, or some other difficult situation. In the United States, the National Institute of Mental Health says more than two million people are affected in any one-year period. The American Psychological Association says panic disorder is two times more likely in women than men. And it can last anywhere from a few months to a lifetime. Panic attacks can be dangerous—for example, if a person is driving at the time. The Chesapeake Bay Bridge in the state of Maryland is so long and so high over the water, it is famous for scaring motorists. There is even a driver assistance program to help people get across. Some people who suffer a panic attack develop a phobia(恐惧病), a deep fear of ever repeating the activity that brought on the attack. But experts say panic disorder can be treated. Doctors might suggest anti-anxiety or antidepressant(抗抑郁的) medicines. Talking to a counselor could help a person learn to deal with or avoid a panic attack. There are breathing methods, for example, that might help a person calm down. Panic disorder is included among what mental health professionals call anxiety disorders. A study published last week reported a link between anxiety disorders and several physical diseases. It says these include thyroid(甲状腺的) disease, lung and stomach problems, migraine headaches(偏头痛) and allergic(过敏的) conditions. Researchers at the University of Manitoba in Canada say that in most cases the physical condition followed the anxiety disorder. But, they say, exactly how the two are connected remains unknown.

单选题The minister Uheaded/U the committee.

单选题Marxism doctrine was spelled out in the Communist Manifesto.

单选题Gooseneck barnacles {{U}}attach{{/U}} themselves to objects such as docks and boats.

单选题The photographs {{U}}evoked{{/U}} strong memories of our holiday in France. A. stored B. blocked C. erased D. refreshed

单选题The landscape can change abruptly after a rainstorm in the Great Sahara Desert. A. quickly B. completely C. gradually D. slightly

单选题The middle-aged man was given a cordial reception because he was Utaken for/U an eminent writer.

单选题There is an abundant supply of salt in the market.

单选题Mary had sold her bike, taken a driving Utest/U and bought a car.