单选题In plane geometry, the sum of the internal angles of any triangle A B C has always equal to 180 degrees.

单选题Physicists have known since the early nineteenth century that all matter is made up of tiny extremely particles called atoms.

单选题According to the passage, which of the following is true about all early domesticated plants?

单选题Primitive humans probably did not (deliberately cook) food until (long) after they had learned (to use )fire for light and (warm.)

单选题According to the passage, when gathering materials to build their nests, sparrowhawks do which of the following?

单选题The International Monetary Fund was created in a effort to stabilize exchange rates without interfering with the healthy growth of trade.

单选题(Few substances) lock less (alike than )coal and diamonds, yet both (are fashioned) (from same) elemental carbon.

单选题16. Lake trout, fish usually (finding) in deep,(cool) lakes, are greenish gray and are(covered) with (pale) spots.

单选题Whydidthestudentmissthelesson?

单选题The word "it" in line 21 refers to

单选题The word "favored" in line 2 is closest in meaning to

单选题1 The youngest child of a prosperous Midwestern manufacturing family, Dorothy Reed was born in 1874 and educated at home by her grandmother. She graduated from Smith College and in 1896 entered Johns Hopkins Medical School. After receiving her M.D. degree, she worked at Johns Hopkins in the laboratories of two noted medical scientists. Reed's research in pathology established conclusively that Hodgkin's disease, until then thought to be a form of tuberculosis, was a distinct disorder characterized by a specific blood cell, which was named the Reed cell after her. 2 In 1906, her marriage to Charles Mendenhall took Reed away from the research laboratory. For ten years, she remained at home as the mother of young children before returning to professional life. She became a lecturer in Home Economics at the University of Wisconsin, where her principal concerns were collecting data about maternal and child health and preparing courses for new mothers. 3 Dorothy Reed Mendenhall's career interests were reshaped by the requirements of marriage. Her passion for research was redirected to public health rather than laboratory science. Late in life, she concluded that she could not imagine life without her husband and sons, but she hoped for a future when marriage would not have to end a career of laboratory research.

单选题The Play: A Streetcar Named Desire One of the most enduring masterpieces of the American theatre is Tennessee Williams" play A Streetcar Named Desire. This modem psychological drama comes short on the heels of another successful Williams" play entitled The Glass Menagerie. Unfortunately, Williams never managed to follow up on these early literary successes. Literary critics and the public alike have warmly applauded both The Glass Menagerie, published in 1945, and A Streetcar Named Desire, which came out a few years later and won the Pulitzer Prize for Drama in 1948. Despite this promising start, none of William"s later fictional work ever lived up to the reputation of his debut pieces. A Streetcar Named Desire was nevertheless enough to secure Tennessee Williams a place amongst the greatest writers of his time. It premiered on December 3, I947 at the Ethel Barrymore Theatre on Broadway and ran uninterrupted until 1949. It turned its playwright into a household name. The plot of the play revolved around the sexually charged conflict between a pretentious Southern belle and a brutish proletarian, who is her brother-in-law. Blanche duBois, who belongs to the fading aristocratic class, looks for shelter at her sister Stella"s house in New Orleans. Fearing the crudeness and vulgarity of her husband, Stanley Kowalski, Stella reluctantly agrees to take her estranged sister in seeing as she suffers immensely from the loss of her ancestral plantation, Belle Reve. The name, which might be translated from French as "beautiful dream," is a subtle allusion to the idealistic world that Blanche lives in. She puts on airs of nobility, and pretends to be charming, educated and refined. Yet all this is nothing but a thin veil to cover her alcoholism and precarious emotional state. In due course, Blanche falls for the aggressive, rough hewn but sensual Stanley, who is at the same time attracted and repulsed by Blanche"s nature. Soon, self-effacing Stella, who has taught herself to love her husband out of a sense of duty and honor, feels betrayed and left out within this curious love triangle. The play comes to a tragic end with Blanche suffering a nervous breakdown and Stanley raping Stella into submission. The play abounds with symbols and allegoric motifs. The title of A Streetcar Named Desire is a reference to the streetcar that Blanche takes in order to reach her sister"s house in the French Quarter of New Orleans. The place where the Kowalski"s reside is ironically termed Elysian Fields after the underworld from Greek mythology. Much like her streetcar journey and doomed stay at Elysian Fields, Blanche"s happiness is short-lived because it steins from pleasure brought about by desire. A S treetcar Named Desire is thus only a prelude to what is to befall Blanche in the near future and the perfect complement to the illusionary world she has built around herself. In actuality, the entire play revolves around the theme of myth and reality. All characters live in a fantasy world, which they have constructed in order to shield themselves from the harsh realities of life and the momentous changes that take place all around them. Blanche deludes herself into believing she is an aristocrat, much like Stella deludes herself into believing she loves Stanley. Stanley himself deludes himself by creating this authoritarian macho-figure who dominates and seduces women, when in fact he is nothing but a self-absorbed loser. Stanley Kowalski"s character has often been mistakenly assumed to be the epitome of the newly established working class. He appears self-assured, but is in reality rather shallow, vulgar and callous. His narrow-minded obsession with money and building a family, as well as his chauvinistic attitude towards women has nothing progressive in it. Stanley rather reflects the mercantile tendencies of the industrial American middle-class, whose selfishness has swept aside the traditional values of societies. Similarly, Blanche is by no means the blasé bourgeois some critics make her out to be. She is the sad relic of a class in demise, namely that of the Old Southern aristocracy. Hers and her sister"s tragedy is the tragedy of all women of the South bereft of the chivalric values to which they have grown accustomed. Just like in old fairy tales, they need to be rescued, but their tragedy is that in capitalist America there is nobody left to rescue them. Glossary revolve: mainly become the topic of something proletarian: relating to proletariat (workers without high status) estranged: quarreled with family or friends and are not communicating with them allegoric: pertaining to allegory; figurative

单选题Whatistheconversationmainlyabout?

单选题The largest of the giant gas planets, Jupiter, with a volume 1,300 times greater than Earth's, contains more than twice the mass of all the other planets combined. It is thought to be a gaseous and fluid planet without solid surfaces, Had it been somewhat more massive, Jupiter might have attained internal temperatures as high as the ignition point for nuclear reactions, and it would have flamed as a star in its own right. Jupiter and the other giant planets are of a low-density type quite distinct from the terrestrial planets: they are composed predominantly of such substances as hydrogen, helium, ammonia, and methane, unlike terrestrial planets. Much of Jupiter's interior might be in the form of liquid, metallic hydrogen, Normally, hydrogen is a gas, but under pressures of millions of kilograms per square centimeter, which exist in the deep interior of Jupiter, the hydrogen atoms might lock together to form a liquid with the properties of a metal. Some scientists believe that the innermost core of Jupiter might be rocky, or metallic like the core of Earth. Jupiter rotates very fast, once every 9.8 hours. As a result, its clouds, which are composed largely of frozen and liquid ammonia, have been whipped into alternating dark and bright bands that circle the planet at different speeds in different latitudes. Jupiter's puzzling Great Red Spot changes size as it hovers in the Southern Hemisphere. Scientists speculate it might be a gigantic hurricane, which because of its large size (the Earth could easily fit inside it), lasts for hundreds of years. Jupiter gives off twice as much heat as it receives from the Sun. Perhaps this is primeval heat or beat generated by the continued gravitational contraction of the planet. Another starlike characteristic of Jupiter is its sixteen natural satellites, which, like a miniature model of the Solar System, decrease in density with distance—from rocky moons close to Jupiter to icy moons farther away. If Jupiter were about 70 times more massive, it would have become a star, Jupiter is the best-preserved sample of the early solar nebula, and with its satellites, might contain the most important clues about the origin of the Solar System.

单选题(In cases of. minor injury (to) the brain. Amnesia is (likely) to be a (temporarily) condition. A. In cases of B. to C. likely D. temporarily

单选题Lowell, Massachusetts, known as the "Spindle City" since 1822 when its first A B textile mills were built, attracted worldwide attention as textile center.

单选题The Threat of the Pandemic Flu Several years ago, the world fell into frenzy when a highly contagious disease called SARS spread all around the globe and infected thousands of people worldwide. This same scenario might repeat itself in the near future. In fact, epidemiologists warn that humanity is long overdue when it comes to the pandemic flu. The last strains of virulent influenza to hit the globe happened as far back as 1957 and 1968. They claimed the lives of millions of people, yet were less deadly than the 1918 pandemic, which killed 40 million worldwide. The discrepancy between these numbers is due to the fact that the later flu strains were less fierce than those that triggered the 1918 pandemic flu. There is no way of knowing the severity of the next influenza virus or the time it will break out. All that scientists know for certain is that a global pandemic is inevitable. It is therefore imperative that all countries are well prepared in advance to meet this potentially deadly epidemic. The World Health Organization is carefully monitoring for any signs of potential trouble. It is particularly analyzing the effects that the current avian flu virus has upon the population of Asia and Europe. In general, influenza viruses are airborne. They are rapidly transferred from the host to a receptor ceil, where they incubate in less than two days. Unlike normal flu viruses that are neutralized by the body"s immune system, pandemic viruses undergo genetic mutations that render them untouchable. For instance, the avian strains of influenza evolved by binding to sialic acid, which enabled them to enter human cells more easily. Alternatively, two strains of influenza could infect the same host cell at the same time and release a pair of viral RNA inside the cell nucleus. When such viral strains mix with one another they produce an extremely contagious pandemic strain. Should an outbreak of such a virus occur, health care workers and governments would have limited time to react. After 30 days of unconstrained spread, the virus would be unstoppable and millions would perish. It is therefore vital that public authorities from around the world communicate with each other over this issue. Prevention is preferable over treatment. Customs and border security have to be aware of any potentially ill people that enter a country. It is recommended that both tourists and business people have a thorough checkup before traveling abroad or returning from a trip overseas. Doctors and health agencies need to be on constant alert and keep any incoming flu patients under surveillance. Often a simple antiviral flu shot administered on time can halt the immediate spread of a virulent disease. One hurdle the world faces right now is the relative lack of appropriate medication. Because flu viruses spread so quickly and soon become resistant to current drugs on the market, it is difficult to create effective anti-flu shots. Moreover, all these shots quickly become outdated due to the fact that evolving virus strains undergo genetic mutations that make them immune to the action of the drug. Given these discouraging circumstances, pharmaceutical companies have little incentive investing in the development of new flu vaccines. The current global supply of antiviral shots would hardly cover the needs of a quarter of the population of the USA. In case of an emergency, decisions have to be made as to who would get these shots first. And virologists still do not know the full extent of side-effects antiviral vaccines may trigger. More research needs to be done to avoid any unforeseen problems caused by their prolonged use. The threat of a pandemic flu is looming large over the head of the entire world population. While antiviral flu shots may be perceived by some as a poor antidote in case of a global pandemic, they are still the only possible cure known today to treat this horrible disease. Without proper preventive treatment, the pandemic flu might have catastrophic consequences that far outreach the fatalities recorded during the 1918 epidemic. Pharmaceutical companies and research institutes must put their heads together to not only develop the best treatment possible, but also to increase the number of currently available medications on the market. At the same time, governments of more developed nations need to offer free resources and information to less prosperous countries in an effort to stop any potential outbreak in its track. Only a concerted effort on all parts will have wide reaching positive effects in the long run. Glossary SARS: Severe A cute Respiratory Syndrome epidemiologist: a person who studies the distribution, effects, and causes of diseases in populations pandemic: describing a widespread epidemic of a disease, one that affects a whole country, continent, etc. virulent: said of a disease; having a rapidly harmful effect loom: to be imminent, especially in some menacing or threatening way

单选题The United States, a nation with a (highly) diversified (economy), is a major (exporter of) grain, fruit, (chemical), aircraft, and cars.