单选题We found （shelter） from the rain under the trees.

单选题In the United States, the need to protect plant and animal species has become a highly controversial and sharply political issue since the passage of the Endangered Species Act in 1973. The act, designed to protect species' living areas, and policies that preserve land and forests compete with economic interests. In the 1990's, for example, the woodcutters in the Western United States were challenged legally in their attempt to cut trees for timber in the Cascade Mountains. The challenge was mounted to protect the endangered spotted owl(猫头鹰), whose remaining population occupies these forests and requires the intact, ancient forest for survival. The problematic situation set the interests of environmentalists against those of corporations and of individuals who stood to lose jobs. After months of debate and legal battles, the fate of the woodcutters—and the owls—was still undecided in mid-1992. Similar tensions exist between the developed and the developing nations. Many people in industrialized nations, for example, believe that developing nations in tropical regions should do more to protect their rain forests and other natural areas. But the developing countries may be impoverished(使穷困), with populations growing so rapidly that using the land is a means to temporarily avoid worsening poverty and starvation. Many of the changes to Earth that concern scientists have the potential to rob the planet of its biological richness. The destruction of Earth' s ozone layer(臭氧层), for example, could contribute to the general process of impoverishment by allowing ultra-violet rays to harm plants and animals. And global warming could wipe out species unable to quickly adapt to changing climates. Clearly, protecting will come only through coordinated international efforts to control human population, stabilize the composition of the atmosphere, and preserve intact Earth' s complex web of life.

单选题These are our motives for doing it.

单选题She gave up her job and started writing poetry.

单选题Students working toward a degree in business are {{U}}likely{{/U}} candidates for careers in the banking industry.

单选题We bad a long conversation about her parents. A. speech B. question C. talk D. debate

单选题The team's Uspirit/U was at the lowest point in the season.

单选题 A. short-term memory B. relearning C. needed D. coded E. recognition F. slow forgetting rate

单选题Many experts remain {{U}}skeptical{{/U}} about his claims. A. doubtful B. untouched C. certain D. silent

单选题Image Martian Dust Particles NASA's Phoenix Mars Lander has taken its first ever picture of a single particle of rusty Martian dust with one of its microscopes. The dust particles of dust were shown at a higher magnification than anything outside of Earth that has been imaged before. The rounded particle measured only about one micrometer, or one millionth of a meter, across. "Taking this image required the highest resolution microscope operated off Earth and a specially designed device to hold the Martian dust," said Tom Pike, a Phoenix science team member from Imperial College London. "We always knew it was going to be technically very challenging to image particles this small." The device that imaged the dust speck is called an atomic force microscope, which maps the shape of particles in three dimensions by scanning them with a sharp tip at the end of a spring. The atomic force microscope can detail the shapes of particles as small as about 100 nanometers. And this won't be the last dust particle that Phoenix will image. "After this first success, we're now working on building up a portrait gallery of the dust on Mars," Pike said. Dust exists everywhere on Mars, coating the surface and giving it its rusty red color. Dust particles also color the Martian sky pink and feed storms that regularly envelope the planet. The ultrafine dust is the medium that actively links gases in the Martian atmosphere to processes in Martian soil, so it is critically important to understanding Mars' environment, the researchers said. The $ 420-million Phoenix mission is analyzing the dust and subsurface ice layers of Mars' arctic regions to look for signs of potential past habitability. The particle seen in the atomic force microscope image was part of a sample scooped by the robotic arm from the "Snow White" trench and delivered to Phoenix's microscope station in early July.

单选题How do you (account) for your absence from the class last Thursday?

单选题John survives on 100 pounds a month. A. puts B. lives C. borrows D. spends

单选题Thinking of the interesting stories helped the time to pass, and the work seemed less Utough/U.

单选题Unfortunately, the new swine flu virus can be transmitted between humans. It is not clear yet how easily it is transmitted, nor how it is transmitted. Almost surely it is transmitted by sneezing and coughing, and by skin-to-skin contact with an infected person. How is the swine flu virus transmitted according to the passage?A. It is very easily transmitted from person to person.B. It is not quite sure how it is transmitted yet.C. It is surely transmitted by sneezing or coughing.D. It is surely transmitted by skin-to-skin contact.

单选题The Polynesians found uses for many indigenous plants.

单选题 Where Have All the Frogs Gone? In the 1980s, scientists around the world began to notice something strange: Frogs were disappearing. More recent research has shown that many kinds of amphibians (两栖动物) are declining or have become extinct. They have been around for a long time - over 350 million years. Why are they dying out now? Scientists are seriously concerned about this question. First of all, amphibians are an important source of scientific and medical knowledge. By studying amphibians, scientists have learned about new substances that could be very useful for treating human diseases. Further research could lead to many more discoveries, but that will be impossible if the amphibians disappear. The most serious aspect of amphibian loss, however, goes beyond the amphibians themselves. Scientists are beginning to think about what amphibian decline means for the planet as a whole. If the earth is becoming unlivable for amphibians, is it also becoming unlivable for other kinds of animals and human, beings as well? Scientists now believe that amphibian decline is due to several environmental factors. One of these factors is the destruction of habitat, the natural area where an animal lives. Amphibians are very sensitive to changes in their habitat. If they cannot find the right conditions, they will not lay their eggs. These days, as wild areas are covered with houses, roads, farms, or factories, many kinds of amphibians are no longer laying eggs. For example, the arroyo toad (蟾蜍) of southern California will only lay its eggs on the sandy bottom of a slow-moving stream. There are very few streams left in southern California, and those streams are often muddy because of building projects. Not surprisingly, the arroyo toad is now in danger of extinction. There are a number of other factors in amphibian decline. Pollution is one of them. In many industrial areas, air pollution has poisoned the rain, which then falls on ponds and kills the frogs and toads that live there. In farming areas, the heavy use of chemicals on crops has also killed off amphibians. Another factor is that air pollution has led to increased levels of ultraviolet (UV) light. This endangers amphibians, which seem to be especially sensitive to UV light. And finally, scientists have discovered a new disease that seems to be killing many species of amphibians in different parts of the world. All these reasons for the disappearance of amphibians are also good reasons for more general concern. The destruction of land, the pollution of the air and the water, the changes in our atmosphere, the spread of diseases - these factors affect human beings, too. Amphibians are especially sensitive to environmental change. Perhaps they are like the canary (金丝雀) bird that coal miners once used to take down into the mines to detect poisonous gases. When the canary became iii or died, the miners knew that dangerous gases were near and their own lives were in danger.

单选题John is collaborating with Mary in writing an article.

单选题The word "Sunset" in the title of this novel most 'probably means

单选题What were the consequences of the decision she had made?

单选题They have the capability to destroy the enemy in a few days. A．possibility B．necessity C．ability D．probability