2020年P(guān)ETS-3考試教材第十八單元：科普

Unit 18 Popular Science

Conversations：

1.Tang Ming and Du Hua,two college students,are discussing computer craze.

Now,Many students have computers.

A computer craze has hit the campus of many colleges of China.

yes,you are right.

If you enter a dormitory,You will find one or two computers there.

It is true that the computer has been used widely in students'studies.

But some students often play computer games.

Rigth.according to the survey,computers greatly influence some students'studies.

In my university,many young video addicts could indulge themselves in games all night long.

Oh.Fortunately,many universities and colleges are aware of such problems and are planning to carry out projects to correct this phenomenon.

It seems to me that the campus computer problems are not a question of the computer itself but of the way of using it.

I agree.

We are sure tha tcolleges and universities can find a good solution to these problems.

2.Wu Li is a salesman.Ma Gang is a customer.

They are talking about exchanging a computer.

What can I do for you?

I bought a computer here last Friday and now it simply does not work.

What's wrong with it?

I'm not sure.

When I turn it on,there's only sould but no words.

Is the screen clear?Not very clear.

Did you try it here before you took it home?yes.It was all right.

But when it got to my office,it didn't work properly.

It's unreasonalbe.

Can you replace it with another one?

I'm afraid not.

Would you send the computer in and we have it checked first?

Then we'll see what we can do about it.

3.Tom and Susan are in Tom's sports car.

They are at a petrol station.

Three gallons of super,please.

Three gallons of super.Yes,sir.

Tom...why don't we get small family car?

What?You mean,sell my sports car?Never!

But it's expensive to run and it's old.

You bought it long before.

Er...excuse me.That's$5.sir.here you are.Oh,and would you check my battery,please?

Check the battery,sir?Certainly.

Don't you remember?

It broke down just before we got married and it was in the garage for a whole week!

This is a wonderful car!It always starts first time!

The battery's all right,sir.Thank you.

It didn't start first time yesterday morning!

That was only because it was so cold!

It's a wonderful engine.just listen to it when I start now!

(Presses starter.Sound of engine turning over but not starting.)

I'm listening,Tom.

Passage Electricity

If you were thirsty,and took a cup to the kitchen sink,you might first turn the tap on just a little way,so that only a thin stream of water came form it.

Then you would turn the tap a bit farther.

Not only would there be more water,but also it would come out with greater force.

If you turned it on as far as it would go,you would get no water in your cup at all,for it would come form the tap in so powerful a jet that it would bounce straight out of the cup again,and most likely drench you.

In that stream of water,then,are three things--or rather,two things and their result.

Firstly,the amount or quantity,or current of water.

Secondly,the pressure pushing it.

And thirdly,the power of the jet,which is the result,or pruduct of the current of water and the force pushing it.cables and overhead lines for carrying electrical current.

Aluminium is another good conductor with a low resistance.

Being light in weight,it is often used for overhead lines,such as you see slung in graceful curves between pylons,but being a soft metal it usually has a steel wire core to give it strength.

Sometimes,however,wires of high resistance are put to special uses.

When electrical energy is taken up in overcoming the resistance of a wire,it produces heat.this makes the sire redhot,as in an electric radiator,or while-hot,as in the filament of a lamp.

Thus from metals of high resistance,we can get either heat or light for our use.

Words and Expressions:

thirsty tap bounce

adj.口渴的n.龍頭v.彈出

drench amp volt

v.使浸透，弄濕n.(電)安培n.(電)伏特，伏

watt circuit pump

n.(電)瓦特n.電路;線路v.為...打氣

 wire resistance ohm

n.電線n.(電)電阻n.(電阻單位)歐姆

conductor diameter lead

n.(電)導體n.直徑n.鉛

nickel cable aluminium

n.鎳n.(電)電纜n.鋁

sling pylon

v.吊n.架高壓電纜的鐵塔

radiator filament

n.散熱器n.燈絲

I've read that,too.But eggs are cheaper than steak.

An uncle of mine doesn't eat anything but steak.

He eats steak for breadkfast.

The best way to lose weight is to eat less and exercise more.

C You should be careful with fires.

People who are not careful cometimes cause fires that burn buildings or forests.

If youa re ever in building,Crawl on the floor to a door and get out.

The smoke and heat from the fire are in the upper part of a room.

The air near the floor is cooler and fresher.

If your clothing get on fire,roll on the ground or wrap yourself in a blanket to shut out the air.

With no air,the fire will go out.

Firemen sometimes put out fires by spraying water on them.

The water cools the burning material so that the fire goes out.

Supplementary Reading

Computers and Crime

No one who reads the newspapers can doubt the seriousness of this country.

Not a day goes by without numberous robberies,rapes,and murders being reported.

In amny cities,It's extremely dangerous to walk the street at night.

Crime is a complex problem with many causes.

Poverty,unemployment,conditions in the cities,and increasing disregard for authority all play their roles and no single remedy is going to solve the problem overnight.

But perhaps at least one of the causes can be dealt with--the inefficiency of the criminal justice system.

For instance,the police usually are able to solve only a fraction of the crimes committed.

And offenders are apprehended,there is usually a long delay in trial and sentencing.

During the delay,the offenders may be out on bail committing more crimes.

Much police work concerns information--information about stolen property,fugitives from justice,the methods of operation of known criminals.

The computer can make an important contribution to processing this information effectively and efficiently.

Unfortunately,there is almost no other area in which computers inspire such fear.

The reason is obvious:the police can initiate proceedings that can take a person's liberty away.

And,sometimes with good reason,not everyone is convinced that those proceedings will be carried out fairly.

Even worse,the police keep records that can haunt us the rest of our lives.

Even those people who have the most to fear from crime may fear even more anything that increase the effectiveness fo the police.

(The fact taht large segments of the population do distrust the police is one more reason there will be no easy solutions to the problem of crime.)

In one way,the computer can be considered a mixed blessing for law enforcement.

To be sure,it helps the police solve crimes and apprehend criminals.

But it also opens up a whole new world of ways to commit crimes.

As far back as 1974,authorities estimated that over 200 million were being lost each year through computer-related crime.

That figure certainly ahs not diminished in the intervening years.