What does the professor imply when he says this？A．At least 4 satellites can make 3D positi

The phrase they do in Paragraph 4 refers to

A．crammers manage to get by with an extremely small amount of studying

B．crammers study only when the threat of taking that class over is very great

C．if crammers are bored and on a borderline D, they might do some homework

D．they clean their room to avoid doing their homework

Which of following can be inferred about the authors opinion of the average studiers?

A．They study sufficiently but don"t work more than necessary.

B．The average studier takes his education seriously and will study with friends.

C．The line between education and having a good time is not so clear.

D．They leave college with a solid education and are much more socially adept.

-tech music systems on drivers?

A．It is convenient to listen to music when drivers are driving.

B．It is one of the causes leading to traffic accidents.

C．It is not easy for drivers to change a cassette or disc.

D．It attracts the drivers" attention and takes their eyes off the roa

In Paragraph 11, why did the author cite psychologist Dr. Robert Wests comments?

A．To indicate that selected music may both improve and distract driving.

B．To prove carefully selected music only benefits those in the high risk group.

C．To show that Mantovani benefits young male drivers when they are on the move.

D．To give evidence that it is hard to persuade young male drivers to listen to Mantovan

ealth when you are at the wheel. (A)Recent research suggests that loud music seriously affects a drivers concentration and psychologists have warned that such music, blasting away inside a car, can be dangerous, especially in traffic queues or on motorways. (B)Heavy metal, with its strong beat, leads to aggressive driving while, at the other end of the spectrum, soothing, melodious music relaxes a driver beyond a safe limit of awareness and into a sleepy haze of inattention. (C) The British Automobile Association, which is concerned with road safety, commissioned research into the relationship between serious accidents and music. (D)It found that men in the 17-25 age bracket were the most dangerous and accident-prone group. It also found that this group listens to music seventy percent of the time when they are on the move. Upbeat tempos, or heavy metal music, played loudly, can bring on a belligerent attitude. The driving style. becomes aggressive and the driver is more apt to take risks. The pace of the driving is governed by the pace and beat of the music. In trials, volunteer drivers subjected to loud music said that, although they didnt necessarily feel inclined to drive faster, they did find themselves making faster gear changes, accelerating more quickly and braking more abruptly. The same drivers, when subjected to slow ballads, admitted that they often found their attention wandering and, during a long motorway journey, at least two of the participants found themselves unconsciously wandering across the lane markings. The comments made by the volunteer drivers, some of whom were newly qualified, were very revealing. Simon, eighteen, told the AA, "The fast rock track out of Bat Out of Hell is potentially lethal. I found myself going faster and faster without even realizing it. " Another volunteer, who had been listening to ZZ Tops greatest hits, said, "I was speeding along singing at the top of my voice and didnt see or hear the fire engine that was trying to overtake me. " Other comments included. "I get lost in my own thoughts..., "Its possible to suffer a dulling of the senses...", "Not hearing other vehicles is a problem..., and "I was revving the engine in time to the beat." Slower, more ambient tracks like Chopin stimulate a change in a persons brain pattern, encouraging Alpha waves and inducing a feeling of well-being. A state of relaxation might be good for us at most other times, but not at the wheel of the car. Psychologist Professor Shirley Fisher warned. "The greatest danger is fatigue at the wheel. Some music can lull you into concentration loss, or even mini-sleep, which can cause horrific accidents. " "Its a matter of selecting your music to suit the conditions. Stimulating music can be useful on long, boring roads but when traffic conditions are difficult, or traffic is heavy, it can distract you. " There is, however, an up side, as AA psychologist Dr. Robert West pointed out: "if some music affects our ability to drive safely, then the reverse is also true. Carefully selected tracks may improve our driving, particularly in the high risk groups. For example, if we could get young male drivers to listen to Mantovani, they would probably slow down. Sadly, I dont think I could persuade many of them to listen, though. " As well as the type of music affecting road safety, the very fact that we have high-tech music systems built into our cars also causes accidents. A recent traffic and road safety report showed that almost forty percent of minor road accidents were caused by people taking their eyes off the road to change a cassette or disc! Whatever our taste in music, or driving style, it looks as if safe driving habits are forced on us in the future. Rover, British Aerospace, Philips and Swedens Road and Traffic Research Institute have combined to produce a car intelligence system that they have named ARIADN (Application of Real-Time Intelligent Aid for Driving), a sophisticated electronic combined navigation-carphone-collision avoidance system that takes advantage of radar to warn the driver when a collision is possible. If the car ceases to be at a safe braking distance from the one in front, ARIADN sends a vibration through the accelerator pedal to warn the driver to slow down. The vibration becomes more and more severe the closer the car gets to the vehicle in front until, if the warnings go unheeded, the engine cuts out and the hazard warning lights go on. So remember, if music is the food of love, do it slowly, especially if youre driving, then we can all "play" on.

The word trials in Paragraph 5 is closest in meaning to ______.

A．inspections

B．experiments

C．tryouts

D．tribulations

According to Paragraph 3, why are there cracks in rocks?

A．Because the rocks are fragile under sunlight.

B．Because the rocks are eroded by wind.

C．Because the liquid and solid water eroded rocks.

D．Because the rocks are broken by floo

in home automation offer homeowners comfort, convenience, security and energy saving. In a fully automated house, you would be able to pick up phone, call your house and instruct it to stop the security system, turn on lights, turn on the compact disc player and start cooking the food in the oven, etc. , all while you were away from home. These and other advances in home automation are fast becoming available to people nowadays, thanks to the ongoing efforts of scores of consumer electronics companies. During the last decade, consumers have readily accepted such technological wonders as microwave ovens, fax machines and cellular phones. Cars are computerized, automated teller machines are widely used in banks and many people have access to personal computers. The interest in home automation, however, is not born of a desire to create a space-age home. It stems from a genuine interest in finding new ways to make a house safe, energy-efficient and comfortable. Take security for example. If there is a fire, an automated house will detect it, turn off the gas, turn on the lights, unlock the doors, set off an alarm and call the fire department. If someone tries to enter your home, a triggered motion detector can turn on floodlights in the yard and instruct your stereo set to produce the sound of a barking dog in order to frighten the person away. If you want to avoid unwelcome guests, you can mount a video camera at the front door, and view visitors on a TV screen. If the caller is someone with a clipboard and a hopeful expression, you can skip that trip to the door. But if it is a friend, you could tap a couple of buttons on the remote control, unlock the door and welcome him in. With home manager, one of several automation systems being sold on the market, you can warm up the master bedroom, kitchen and bathroom in the morning before the alarm goes off. Or you can program it to keep your childrens room at a constant temperature. In midsummer, you can even instruct sensors in the house to open skylights, turn on the ceiling fans and close the curtains when the house reaches a certain temperature. The increase of working couples and single people living alone means there is less time for and interest in menial tasks. Why not automate these tasks whenever possible? Home control systems also offer a lot of conveniences. First of all, you can program your house to do certain things at different times of the day or for different scenarios. A "wake-up mode", for instance, might turn off the security alarm, turn on the kitchen lights, turn up the furnace, heat water and start the coffee pot. A "romantic mode" might allow you, with the flip of a switch, to dim the lights, play romantic music and light the fireplace. And an "unoccupied mode" will arm the security system and randomly turn lights on and off in different rooms. All of these functions can be controlled while in the house or remotely from a phone or computer. In addition, home automation offers tremendous lifestyle. improvements for elderly and disabled people. For those who cant push a button or flip a switch, a voice command can be used to activate security cameras, turn on the stereo volume or drop the room temperature a few degrees. The click of remote control could turn on the oven, close the window or open the door. So, what is home automation exactly? In short, it is actually a combination of several things including microprocessors, enhanced power line transmission, computer chips, telephone and cable wiring, infrared sensors and radio frequency waves.Narrator Listen to a talk on home automation in a mechanical engineering class. Now get ready to answer the questions. You may use your notes to help you answer.

What is the talk mainly about?

A．The differences between traditional and automated houses.

B．The advantages of automated houses.

C．The tendency of home automation.

D．The history of automation technology.

What does that mean?

A．He isn"t sure of the membership fee.

B．He can"t decide which group to join.

C．He can"t remember the phone number.

D．He doesn"t like to visit the advisor.

What is the students attitude toward the language club?

A．He wants to join the club.

B．He thinks the charge is high.

C．He thinks the activities are dull.

D．He likes the debate group best.

Why does the professor mention paper clips?

A．To make an analogy to atoms.

B．To do a chemical experiment.

C．To show the usage of paper clips.

D．To provide some useful stationery.