单选题Fireworks, ______ originated centuries ago in China, were brought to Europe by Marco Polo.

单选题Tom doesn’t think that the ______ situation here is as good as his hometown' s.

单选题Directions:Forthispart,youareallowed30minutestowriteashortessay.Youshouldstartyouressaywithabriefdescriptionofthepictureandthenexpressyourviewsontheindependenceofyoungpeopleinmodernsociety.Youshouldwriteatleast120wordsbutnomorethan180words.

单选题Men could directly turn back to Greece and Rome for instruction, for correction, and for inspiration in the following fields of their work except ______.

单选题The evolution of sex ratios has produced, in most plants and animals with separate sexes, approximately equal numbers of males and females. Why should this be so? Two main kinds of answers have been offered. One is couched in terms of advantage to population. It is argued that the sex ratio will evolve so as to maximize the number of meetings between individuals of the opposite sex. This is essentially a "group selection" argument. The other, and in my view correct, type of answer was first put forward by Fisher in 1930. This "genetic" argument starts from the assumption that genes can influence the relative numbers of male and female offspring produced, by an individual carrying the genes. That sex ratio will be favored which maximizes the number of descendants an individual will have and hence the number of gene copies transmitted. Suppose that the population consisted mostly of females: then an individual who produced sons only would have more grandchildren. In contrast, if the population consisted mostly of males, it would pay to have daughters. If, however, the population consisted of equal numbers of males and females, sons and daughters would be equally valuable. Thus a one-to-one sex ratio is the only stable ratio; it is an "evolutionarily stable strategy." Although Fisher wrote before the mathematical theory of games had been developed, his theory incorporates the essential feature of a game-that the best strategy to adopt depends on what others are doing. Since Fisher's time, it has been realized that genes can sometimes influence the chromosome or gamete in which they find themselves so that the gamete will be more likely to participate in fertilization. If such a gene occurs on a sex-determining (X or Y) chromosome, then highly aberrant sex ratios can occur. But more immediately relevant to game theory are the sex ratios in certain parasitic wasp species that have a large excess of females. In these species, fertilized eggs develop into females and unfertilized eggs into males. A female stores sperm and can determine the sex of each egg she lays by fertilizing it or leaving it unfertilized. By Fisher's argument, it 'should still pay a female to produce equal numbers of sons and daughters. Hamilton, noting that the eggs develop within their host--the larva of another insect--and that the newly emerged adult wasps mate immediately and disperse, offered a remarkably cogent analysis. Since only one female usually lays eggs in a given larva, it would pay her to produce one male only, because this one male could fertilize all his sisters on emergence. Like Fisher, Hamilton looked for an evolutionarily stable strategy, but he went a step further in recognizing that he was looking for a strategy.

单选题{{B}}Passage 4{{/B}} Violin prodigies, I learned, have come in distinct waves from distinct regions. Most of the great performers in the late 19th and early 20th centuries were born and brought up in Russia and Eastern Europe, I asked Isaac Stern, one of the world's greatest violinists the reason for this phenomenon. "It is very clear," he told me, "They were all Jews (犹太人) and Jews at the time were severely oppressed and ill-treated in that part of the world. They were not allowed into the professional fields, but they were allowed to achieve excellence on a concert stage." As a result, every Jewish parent's dream was to have a child in the music school because it was a passport to the West. Another element in the emergence of prodigies, I found, is a society that values excellence in a certain field to nurture (培育) talent. Nowadays, the most nurturing societies seem to be in the Far East. "In Japan, a most competitive society, with stronger discipline than ours." says Isaac Stem, children are ready to test their limits every day in many fields, including music. When Western music came to Japan after World War Ⅱ, that music not only became part of their daily lives, but it became a discipline as well. The Koreans and Chinese as we know, are just as highly motivated as the Japanese. That's a good thing, because even prodigies must work hard. Next to hard work, biological inheritance plays an important role in the making of a prodigy. J. S. Bach, for example, was the top of several generations of musicians, and four of his sons had significant careers in music.

单选题 Listen to the following passage. Altogether the passage will be read to you four times. During the first reading, which will be done at normal speed, listen and try to understand the meaning. For the second and third readings, the passage will be read sentence by sentence, or phrase by phrase, with intervals of 15 seconds. The last reading will be done at normal speed again and during this time you should check your work. You will then be given 2 minutes to check through your work once more. Stress in Life All of us experience stress, to one degree or another, in our everyday lives.

单选题After the music had ______ there was a storm of applause.

单选题Five minutes earlier, ______ we could have caught the last train. A. and B. but C. or D. so

单选题The official was arrested for inability to ______ all his fortune he has enjoyed.

单选题This summer trainers hope to ______.

单选题During our stay m Paris we were splendidly ______ by the Italian Ambassador. A. sustained B. maintained C. retained D. entertained

单选题He kept a ______ hold on her hand as he helped her over the fence.

单选题With her management skills and his marketing expertise, they make a ______ combination.

单选题______ would you solve the problem if this method failed? ( )

单选题Directions:Forthispart,youareallowed30minutestowriteanessaybasedonthepicturebelow.Youshouldstartyouressaywithabriefdescriptionofthepictureandthenexpressyourviewsone-reading.Youshouldwriteatleast120wordsbutnomorethan180words.

单选题 Google researchers have used artificial intelligence (AI) to teach robots how to move like real animals (in this case, dogs). They describe their experiment in a blog released this week. 'First, we describe how robots can learn to move like a real animal by imitating their motions, producing fast and fluent movements like running slowly and hopping. Then, we discuss a system for automating the training of moving skills in the real world, which allows robots to learn to walk on their own, with minimal human assistance,' shared in the blog Xue Bin (Jason) Peng, Student Researcher and Sehoon Ha, Research Scientist, Robotics at Google. They achieved this impressive feat by using something called reinforcement learning (RL). They began by taking a reference video recorded from an animal and using RL to get the robot to imitate an animal's movement. 'By providing the system with different reference motions, we are able to train an animal-shaped robot to perform a diverse set of agile behaviors, ranging from fast walking to dynamic hops and turns. The policies are trained primarily in simulation(模拟，模仿), and then transferred to the real world using a space adaptation technique that can efficiently adapt a policy using only a few minutes of data from the real robot,' wrote the researchers in their blog. However, it is a well-known fact that simulators provide a poor approximation of the real world, meaning that simulations don't perform well in reality. This is where the researchers decided to use a sample-efficient space adaptation technique. They did so by introducing an element of randomness to the physical parameters(参数) used in the simulation by varying physical quantities, such as the robot's mass and friction. This resulted in a machine learning model that could account for all kinds of small changes and the complications they create. The end result is a robot that moves like a real dog. This kind of work is crucial as it can open opportunities to use robots to do sophisticated tasks in the real world.

单选题The red color can stimulate all our ______, including appetite.

单选题They are meticulous in work, well aware a careless mistake will cost the company millions of pounds.