PERTURB: SERENITY ::A．denounce : rantB．interdict : protectionC．purify : imperfectionD．vex

PERTURB: SERENITY ::

A．denounce : rant

B．interdict : protection

C．purify : imperfection

D．vex : irritation

E．fondle : attachment

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发布时间：2020-07-28

更多“PERTURB: SERENITY ::A．denounce : rantB．interdict : protectionC．purify : imperfectionD．vex”相关的问题

第1题

The underlined word "perturb" in the first paragraph most probably means ______.A．modifyB．

The underlined word "perturb" in the first paragraph most probably means ______.

A．modify

B．neglect

C．permeate

D．upset

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第2题

What difference does it make if we read texts displayed on a computer screen instead of on

paper printed with ink？ The computer certainly does not guarantee deeper comprehension, greater subtlety of mind, or a wider range of imaginative reference. The mediation of a computer, however, puts new powers at the disposal of intelligence. For one thing, the computer itself can do simple reading--as I have noted, it can "read" an immense body of literature in search of designated(指定的)words. As anyone knows who has ever spent days in libraries in search of errant information, simply identifying relevant sources absorbs inordinate amounts of time in research. The objection may be raised that a search of texts by computer may block the occasional(偶然发现的)discoveries that occur while browsing in the stacks of great libraries. No member of the academy need fear that the use of a computer will keep him from the stacks, but browsing is, if anything, easier if texts can be called up on a screen in the serenity(宁静)of one's chosen surroundings.

The great deficiency of libraries, as we know them, is that while titles are catalogued, the libraries have no master indexes of the contents of books. Individual volumes, it is true r have indexes, often of inferior quality, but even the best indexes must be examined one at a time. The great advantage of the electronic library is that a computer could search and analyze its contents without proceeding volume by volume. As work in artificial intelligence develops, computer systems may also become adept at more complex tasks, such as summarizing texts, which has been accomplished experimentally.

What does the writer mainly talk about in this passage？

A．The deficiencies of the library in providing information.

B．The different applications of the computer and the library.

C．The advantages and disadvantages of the computer and library.

D．The advantages of the computer in search of information.

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第3题

Meteors are ephemeral. They will usually vanish before you have a chance to point them out

to somebody else. This makes them suitable for starry-eyed lovers to wish upon, but modern technology can put shooting stars to more profitable use. Next time you see one, bear in mind that a dispatcher may be using it to help him marshal a fleet of long-distance lorries.

To human eyes, a meteor is beautiful. To a radio wave, it is just another thing to bounce off, and bouncing radio waves off the sky is not new. Left to themselves radio waves travel in straight lines, which limits their range. To get them round corners, and over the horizon, they need something to bounce off. In the ionosphere—the uppermost level of the atmosphere—the sun's rays break down molecules into positively charged ions and free electrons. These can reflect (and refract) radiation. The ionosphere let Marconi and his contemporaries send radio messages over long distances.

When a pebble falls from space into the atmosphere, moving at tens of kilometers a second, it gets rid of a lot of energy. Like the energy from the sun's rays, this ionizes the molecules of the atmosphere. The meteor's 10—20km path is densely packed with ions. By the 1930s, radio waves bounced off meteor trails had been used by scientists to determine the speed, height and direction of meteors.

The obvious disadvantage of meteors—the fact that they are so transient—might suggest that bouncing radio waves off their trails would remain the preserve of scientists. In overall quantity, though, meteors bid fair to make up what they lack in constancy. On an average day there are a million reasonable-sized ones (one gram), 400 million smaller ones (one-hundredth of a gram), and 160 billion even tinier ones (one ten-thousandth of a gram).

Meteors also have advantage. The greater density of ions in a meteor trail makes it less susceptible to the many things which perturb the ionosphere, and hence the quality of radio signals that bounce off it—such as time of day, weather conditions, sun spots or indeed intrusive meteors. This immunity from "noise" matters to people who want to send digital data. Radio hams may enjoy the tribulations of chit-chat through adversity and static, but such a noisy medium is not good for transmitting error-free sequences of 0s and 1s. That is why meteor-burst communication (MBC) comes into its own when small amounts of data need to be gathered from many places fairly quickly.

A system under construction to monitor the flow of the Nile provides an example. A master transmitter sends a radio "probe" into the sky in roughly the direction of the target. When a conveniently aligned meteor materializes, the probe bounces off it and reaches the receiver. When the receiver hears its master's voice it responds along the same path, spurting out data about the river's recent behavior. The master station acknowledges receipt, gives any further instructions and signs off.

It then directs its probe towards the next of the 250 outstations. Depending on the system's sensitivity, the wait between suitably aligned meteors varies between four seconds and ten minutes. The bursts of communication between master and out-stations may take as little as tenth of a second. It must be completed in the second it takes for the meteor's trail to dissipate.

In America, Meteor Communications of Kent, Washington, is the biggest and oldest of the MBC companies. It has provided meteor-burst equipment for 14 years. Its devices have been planted along the Chinese-Russian border to send short encoded messages back to Beijing. Other systems in Argentina, Australia, Canada, Indonesia, South Africa and Europe have been set up to monitor a variety of things, solar radiation, tides, water supplies, motorway fog, snow conditions and the like.

The military applications are clear, remote unmanned stations could sense approaching enemy ships, a

A．mysterious

B．transient

C．unique

D．wired

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