According to the professor, how did photojournalism make cur..

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第1题

Experts often place non-experts in a(n) situation by claiming legitimacy for their own contribution.

第2题

An introductory sentence to a brief summary of the passage is given below. Complete the summary by adding the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not given in the passage or are minor ideas in the passage. This question is worth 2 points. Natural selection is the name given by Darwin to the process whereby new species evolve over time as individuals with useful traits survive and reproduce, passing those traits on to new generations. ____________ ____________ ____________ Answer Choices 1. Darwin believed that natural selection favored organisms that had traits that could help them find food and survive predator attacks and environmental pressures. 2. Darwin explained advanced traits that did not seem to affect an organisms survival as being characteristics useful in finding a mate. 3. Moths near industrial centers evolve dark coloration when the trees in which they live are blackened by pollution from nearby factories. 4. Recently, scientists have expanded the idea of natural selection to include traits that benefit the species as a group, even when those traits seem harmful to the particular individuals who possess them. 5. The peacocks colorful tail feathers are meant to attract peahens, which view the bright colors involved in the display as a sign of the males good health. 6. Religious groups opposition to evolutionism has led some schools to reconsider teaching it, even though it is an established scientific theory with much evidence to prove it.

Wegener based the theory of Continental Drift on all of the following observations EXCEPT

A．opposition of climates.

B．fit of continents.

C．similarities of living animals.

D．similarities in rocks and ic

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第3题

According to paragraph 6, all of the following statements about the construction of the monument on Mount Rushmore are true EXCEPT:

A．Lincoln Borglum completed the project his father began.

B．It took less than fifteen years to complete the monument.

C．Few deaths occurred as a result of the construction.

D．The monument was created, in part, by the use of dynamit

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第4题

Why does the professor mention the expressions "mother tongue" and "motherese"？

A．To prove that mothers are better language role models than fathers.

B．To illustrate how parents provide a support system for language learning.

C．To compare normal speech patterns with the baby talk that parents use.

D．To argue that second language learning is more difficult for adults.

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第5题

Look at the four squaresthat indicate where the following sentence could be added to the passage. Even those ancient pioneers of civilization, the Greeks, mourned the lost innocence. Where would the sentence best fit？

A．Square Ａ.

B．Square Ｂ.

C．Square Ｃ.

D．Square Ｄ.

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第6题

听力原文：Narrator Listen to part of a discussion in an astronomy class. Professor So far as we know, most of the matter in the universe is in the form. of stars. The majority of stars, uh...including our sun, are clouds of gas and are maintained at a high temperature. Well, how can they keep at such a high temperature... Student A The burning of the energy liberated by the... the thermonuclear reactions in their centers. Professor Right! Due to the thermonuclear reactions. But do you know how we gain knowledge of the stars and get to know how they evolve？ ...By studying the visible light they emit. The birth of stars, however, cant be followed by an optical telescope, since it takes place in regions of space from which light cannot escape. To study this process, therefore, astronomers have to make use of telescopes operating at other wavelengths. The recent technical developments in radio, millimeter-wave and uh...infra-red astronomy, have turned the study of star-formation into one of the most exciting areas of astronomy. The birth of a star is a rare, slow event; all but a very few of the stars that are visible to the naked eye have existed longer than mankind. So, we must first consider the evidence that new stars are now being formed at all. Student B Do you mean that new stars are being formed at any time？ Professor Yep! The energy, say, uh...radiated into space by a normal, so-called "main sequence" star, is...generated by the uh...the conversion of hydrogen to helium. Here, you may ask what a main sequence star is. OK...the main sequence refers to a major grouping of stars that uh...forms a relatively narrow band from the upper left to the lower right, when plotted according to luminosity, that is, how bright it is, and surface temperature, on the Hertzsprung-Russell diagram. Student A You just mentioned that stars are being formed at any time, but can we...by any means, know the potential lifetime of a star？ Professor Yeah, thats right what Im gonna explain. If we compare the mass of hydrogen "fuel"—just now I mentioned the conversion of hydrogen to helium and thus energy is generated—the mass of hydrogen fuel in a main-sequence star with the rate at which energy is being emitted, we can estimate its potential lifetime. It is found that the lifetime of a star depends strongly on its mass—low mass stars are small, cool and long-lived, while high mass stars are large, hot and short-lived. Student A So, professor, can we simply say that the heavier the star is, the shorter it lives？ Professor Well, youve right got it, I should say. Lets uh...take our sun for example. Our sun is now half-way through its total lifetime of about...uh... 10 billion years, but a star with a mass thirty times greater than the sun would live for only a few million years. We know, therere many bright stars we can see existing in the space. This, in some way, implies that star formation must have taken place over the past few million years. Since our galaxy is some ten thousand million years old, it is reasonable to assume that somewhere in the galaxy, the same process is taking place even now. Student B But how are these stars formed？ Professor Ah...thats the point. According to the observation, those hot bright stars are almost always in the nearby areas of interstellar gas clouds. Student B This may indicate what？ Student A Maybe the birth of stars is related to the gas clouds. Professor Exactly! This leads us to conclude that it is out of such clouds that new stars condense. The internal gravity of an interstellar gas cloud tends to make it shrink, and the thermal pressure tends to make it expand. James Jeans, in 1926, showed that a cloud of a given temperature and density can collapse only if its mass is greater than a certain minimum value. Its right a balance between these two actions, say, shrink and expand, that keeps the evolution of a gas cloud. Well, if the balance does not exist any longer, the cloud will start collapsing. Um...for example, a typical cloud with a temperature of uh... 100 000 degree centigrade and a density of 100 hydrogen atoms per cubic centimeter has to be 3 000 times more massive than the sun in order to start collapsing. Once the collapse process has started and the density of hydrogen atoms of the cloud has risen significantly, the fragmentation into smaller cloudlets will take place. And, subsequently, these cloudlets eventually collapse to form. individual stars. Therefore, the theory of uh...gravitational condensation, predicts...well, in agreement with observation, that new stars form. in clusters containing hundreds of thousands of stars rather than as isolated entities. Now get ready to answer the questions. You may use your notes to help you answer. 12. What is the discussion mainly about？ 13. According to the professor, which of the following causes the evolution of a gas cloud into a star？ 14. The professor mentions the energy that maintains the stars at a high temperature. Where does the energy come from？ 15. According to the professor, what is the relation between the mass and the lifetime of a star？ Listen again to part of the lecture. Then answer the question. Professor Therefore, the theory of uh... gravitational condensation, predicts... well, in agreement with observation, that new stars form. in clusters containing hundreds of thousands of stars rather than as isolated entities. 16. What can be inferred from the lecture？ 17. According to the lecture, how are the individual stars formed？Narrator Listen to part of a discussion in an astronomy class. Now get ready to answer the questions. You may use your notes to help you answer.

What is the discussion mainly about？

A．The evolution of interstellar gas clouds.

B．The lifetime of stars.

C．The quality of main-sequence stars.

D．The formation of stars.

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第7题

The word mild in Paragraph 4 is closest in meaning to______.

A．minor

B．serious

C．long

D．kind