LED（Light Emitting Diode），中文名叫发

共用题干
Computer Mouse The basic computer mouse is______(51)amazingly clever invention with a relatively simple design that allows us to point at things on the computer and it is very productive.Think of all the things you can do with a mouse like selecting text for copying and pasting , drawing , and even scrolling（滚动）on the page with the newer mice with the wheel.Most of us use the computer mouse daily without stopping to think how it______(52)until it gets dirty and we have to learn how to______(53)it.We learn to point at things______(54)we learn to speak,so the mouse is a very natural pointing device.Other computer pointing devices include light pens,graphics tablets and touch screens,but the mouse is still our workhorse. The computer mouse was_____(55)in 1964 by Douglas Englehart of Stanford University.As computer screens became more popalar and arrow keys were used to move around a body of text,it became clear that a pointing device that allowed easier motion through the text and even selection of text would be very useful.The introduction of the mouse,with the Apple lisa computer in 1983,really started the computer public on the road to relying on the mouse_____(56)routine computer tasks. How does the mouse work?We have to start at the bottom,so think upside down for now.It all starts with the mouse ball.As the mouse ball in the bottom of the mouse rolls over the mouse pad,it presses against and turns two shafts（轴）.The shafts are connected to wheels with several small holes in them.The wheels have a pair of small electronic light-emitting devices______(57) light-emitting diodes(LED)mounted on either side.One LED sends a light beam to the LED on______(58)side.As the wheels spin and a hole rotates by,the light beam gets through to the LED on the other side.But a moment______(59)the light beam is blocked until the next hole is in place.The LED______(60)a changing pattern of light, converts the pattern______(61)an electronic signal,and sends the signal to the computer through wires in a cable that goes out of the mouse body.This cable is the tail that helps give the mouse its name.The computer interprets the signal to tell it where to position the cursor on the computer______(62). So far we have only discussed the basic computer mouse that______(63)of you probably have or have used.One problem with this design is that the mouse gets dirty as the ball rolls over the surface and picks up dirt.______(64)you have to clean your mouse.The newer optical mice______(65)this problem by having no moving parts.

61._________
A:in
B:from
C:for
D:into

共用题干
第三篇

Weaving with Light

In the Sierra Madre mountain range of west central Mexico,the native Huichol people live much the
way their ancestors did一without electricity,That’s because it's too expensive to string power lines to the
remote mountain areas where they live.To help support themselves,the Huichol create beautiful artwork.
They sell their art in cities hundreds of miles away from their villages.And without electricity一at home or
on the road,they can only work during daylight hours?When it gets dark,they must stop whatever they're
doing.
Now，a team of scientists,designers,and architects is using new technologies to provide the Huichol
with light after the sun sets.The scientists'technique involves weaving tiny electronic crystals into fabrics
that can be made into clothes,bags,or other items.
By collecting the sun’s energy during the day,these lightweight fabrics provide bright white light at
night一 Their inventors have named the fabrics" Portable（轻便的）Lights."Portable Lights have the potential
to transform the lives of people without electricity around the world.
At the core of Portable Lights technology are devices called high-brightness light-emitting diodes（高亮
度发光二极管）,or HB LEDs. These tiny lights appear in digital clocks, televisions, and streetlights.
LEDs are completely different from the light bulbs（灯泡）.Most of those glass bulbs belong to a type
called incandescent lights（白炽灯）.Inside, electricity heats a metal coil（线圈）to about 2. 200 degrees
Celsius.At that temperature,bulbs give off light we can see.Ninety percent of energy produced by mnean-
descent lights,however,is heat一and invisible.With all that wasted energy,bulbs burn out quickly. They
are also easily broken.
LEDs,on the other hand,are like tiny pieces of rock made up of molecules（分子）that are arranged in
a crystal structure.When an electric current passes through a LED,the crystal structure produces light. Un-
like incandescent bulbs,they can produce light of various colors.Within a LED,the type of molecules and
their particular arrangement determine what color is produced.

LEDs are different from light bulbs in that__________.
A:LEDg are made up of tiny pieces of rock
B:LEDs can send out light of different colors
C:LEDs belong to incandescent lights
D:LEDs look like crystals

共用题干
Computer Mouse

The basic computer mouse is an amazingly clever invention with a relatively simple design that allows us to point at things on the computer and it is very productive.Think of all the things you can do with a mouse like selecting text for copying and pasting,drawing,and even scrolling on the page with the newer mice with the wheel. Most of us use the computer mouse daily without stopping to think how it works until it gets dirty and we have to learn how to clean it. We learn to point at thing before we learn to speak,so the mouse is a very natural pointing device.Other computer pointing devices include light pens,graphics tablets and touch screen,but the mouse is still our workhorse.
The computer mouse was invented in 1964 by Douglas Englehart of Stanford University.As computer screens became popular and arrow keys were used to more around a body of text,it became clear that a pointing device that allowed easier motion through the text and even selection of text would be very useful.The introduction of the mouse,with the Apple Lisa computer in 1983,really started the computer public on the road to relying on the mouse for routine computer tasks.
How does the mouse work?We have to start at the bottom,so think upside down for now. It all starts with mouse ball. As the mouse ball in the bottom of the mouse rolls over the mouse pad,it presses against and turns two shafts.The shafts are connected to wheels with several small holes in them. The wheels have a pair of small electronic light-emitting devices called light emitting diodes (LED)mounted on either side.One LED sends a light beam to the LED on the other side.As the wheels spin and a hole rotates by,the light beam gets through to the LED on the other side.But a moment later the light beam is blocked until the next hole is in place.The LED detects a changing pattern of light,converts the pattern into an electronic signal,and sends the signal to the computer through wires in a cable that goes out the mouse body.This cable is the tail that helps give the mouse its name.The computer interprets the signal to tell it where to position the cursor on the computer screen.
So far we have only discussed the basic computer mouse that most of you probably have or have used.One problem with this design is that the mouse gets dirty as the ball rolls over the surface and picks up the dirt. Eventually you have to clean your mouse. The newer optical mice avoid this problem by having no moving parts.

When an ordinary computer mouse gets dirty,it has to be replaced with a new one.
A:Right
B:Wrong
C:Not mentioned

共用题干
第三篇

Weaving with Light

In the Sierra Madre mountain range of west central Mexico,the native Huichol people live much the
way their ancestors did一without electricity,That’s because it's too expensive to string power lines to the
remote mountain areas where they live.To help support themselves,the Huichol create beautiful artwork.
They sell their art in cities hundreds of miles away from their villages.And without electricity一at home or
on the road,they can only work during daylight hours?When it gets dark,they must stop whatever they're
doing.
Now，a team of scientists,designers,and architects is using new technologies to provide the Huichol
with light after the sun sets.The scientists'technique involves weaving tiny electronic crystals into fabrics
that can be made into clothes,bags,or other items.
By collecting the sun’s energy during the day,these lightweight fabrics provide bright white light at
night一 Their inventors have named the fabrics" Portable（轻便的）Lights."Portable Lights have the potential
to transform the lives of people without electricity around the world.
At the core of Portable Lights technology are devices called high-brightness light-emitting diodes（高亮
度发光二极管）,or HB LEDs. These tiny lights appear in digital clocks, televisions, and streetlights.
LEDs are completely different from the light bulbs（灯泡）.Most of those glass bulbs belong to a type
called incandescent lights（白炽灯）.Inside, electricity heats a metal coil（线圈）to about 2. 200 degrees
Celsius.At that temperature,bulbs give off light we can see.Ninety percent of energy produced by mnean-
descent lights,however,is heat一and invisible.With all that wasted energy,bulbs burn out quickly. They
are also easily broken.
LEDs,on the other hand,are like tiny pieces of rock made up of molecules（分子）that are arranged in
a crystal structure.When an electric current passes through a LED,the crystal structure produces light. Un-
like incandescent bulbs,they can produce light of various colors.Within a LED,the type of molecules and
their particular arrangement determine what color is produced.

The central part of the Portable Lights technology is_________.
A:glass bulbs
B:digital clocks
C:incandescent lights
D:HB LEDs