大学英语四级模拟试题(9)

　　Directions： There are four reading passages in this part. Each passage is followed by some questions. For each question there are four suggested answers marked A, B, C and D. You should choose the one best answer and blacken the corresponding letter on the ANSWER SHEET with a pencil. Passage 1
　　How do you send a message to a submerged submarine, particularly one carrying mi Water may not look like a barrier to communications, but appearances are deceiving. Water strongly absorbs all electromagnetic waves except blue green light and extremely low frequency radio waves. The very low frequency waves now used to contract submarines penetrates only a short distance into the ocean, so the craft must either surface or send up and antenna （天线） to receive messages, thereby increasing its weakness. A laser system —— accurate over long distances and capable of carrying more data than the very low frequency waves —— would talk to submarine at their normal depths.
　　In the system, a very broad beam spreading out freely in all directions would be scanned （扫描） over thousands of square miles of ocean so that it wouldn't endanger boats, birds or fish——or the submarines it is supposed to reach.
　　Since only a small fraction of the laser system will make its way through the air and ocean, receivers mounted on the submarines must be able not only to detect the laser but also to discriminate between it and sunlight. So, military scientists are now working hard on special filter that allow through only the precise wavelengths emitted by the laser. The filtered light, when transformed into electrical signal, can then be decoded. Military planners are confident that laser communication with submarines is feasible.
　　1. Which of the following does the passage mainly discuss？
　　A. Missiles carried by submerged submarines. B. Messages sent by submerged submarines. C. Blue-green lasers used by submerged submarines. D. The way to send a message to submerged submarines.
　　2. Which of the following is TRUE according to the passage？
　　A. Water is a barrier to radio communication. B. Lasers have found wide application in submarine communication. C. Water absorbs all kinds of electromagnetic waves. D. Very low frequency radio waves cannot be used to contact submarines.
　　3. Which of the following is NOT true of a laser system？
　　A. It is able to make its way through water. B. It is able to communicate with submarines at work. C. Its beam reaches a submerged submarine with the help of an antenna. D. It is able to carry more data than low frequency waves.
　　4. The reference word “it” （Sentence 1, para.3） refers to .
　　A. the air B. the laser beam C. the ocean D. the submarine
　　5. Who would be very much interested in the passage？
　　A. Missile builders B. Military scientists C. Fishermen D. Ship builder
　　Passage 2
　　The West begun to take more notice of the East. The fifth volume of an enormous work re-assessing the Chinese contribution to science and technology is to be published next year. The first volume, which was published twenty years ago, set the tone for the whole work. In it, evidence was given to show that many inventions which, until then, western historians had claimed for Europe, were made first in China. The attempt to rewrite the intellectual history of the world was not received without protest by some reputable historians. However, the evidence that has been presented so far in the first four volumes has persuaded many historians who were skeptical at first. China's invention of paper, printing, the magnetic compass and gunpowder has never been disputed, but this new history has added advanced bridge design, mechanical clocks, paddle boats and many other inventions to the list.
　　In the four volumes published so far no attempt has been made to explain why China has not kept up with the West in science and technology in modern times. It is probable that the answer is to be found in the social and economic history of China, where a static society under a relatively benevolent regime of scholar-gentry contrasts with the potentially revolutionary and dynamic society of the West at the end of the Middle Ages. In recent years, the Chinese government has been making every effort to catch up with the West again, and there is little doubt that the gap is being reduced year by year. But will China avoid the West's mistakes？
　　6. So far, how many volumes have been published？
　　A. Five. B. Four. C. Three. D. None.
　　7. The first volume was published .
　　A. ten years ago B. last year C. five years ago D. twenty years ago
　　8. In Line 7, the word “skeptical” means .
　　A. doubtful B. worried C. sad D. angry
　　9. Which of the following is not mentioned in the passage？
　　A. Gunpowder. B. Needle. C. Paddle boats. D. Bridge design.
　　10. The best title for this passage is .
　　A. China's Inventions B. Comparisons Between the East and the West C. China Is Catching Up D. Situations in China