1.题干：an explanation of the factors affecting the transmission of information
（C9-T3-R3 T27）
原文：Information theory generalises this idea via theorems that capture the effects of noise with mathematical precision. In particular, Shannon showed that noise sets a limit on the rate at which information can pass along communication channels while remaining error-free.
同义替换：
An explanation --- generalises this idea
Factors --- effects
The transmission of information --- information can pass along communication channels
2.题干：an example of how unnecessary information can be omitted
（C9-T3-R3 T28）
原文：As mobile phone text messages like ‘I CN C U’ show, it is often possible to leave out a lot of data without losing much meaning.
同义替换：
An example --- mobile phone text messages like ‘I CN C U’
Unnecessary information --- leave out a lot of data
Be omitted --- without losing much meaning
3.题干：a reference to Shannon’s attitude to fame（C9-T3-R3 T29）
原文：While at Bell Laboratories, Shannon developed information theory, but shunned the resulting acclaim.
同义替换：
Shannon’s --- Shannon
Attitude to fame --- shunned the resulting acclaim
4.题干：details of a machine capable of interpreting incomplete information
（C9-T3-R3 T30）
原文：The Voyager spacecraft transmitted data using codes which added one extra bit for every single bit of information; the result was an error rate of just one bit in 10,000 - and stunningly clear pictures of the planets.
同义替换：
A machine --- the Voyager spacecraft
capable of interpreting incomplete information --- stunningly clear pictures of the planets
5.题干：a detailed account of an incident involving information theory
（C9-T3-R3 Q31）
原文：In April 2002 an event took place which demonstrated one of the many applications of information theory.
同义替换：
A detailed account --- demonstrated one
An incident --- an event
Involving --- applications of
6.题干：a reference to what Shannon initially intended to achieve in his
research
（C9-T3-R3 Q32）
原文：This all seems light years away from the down-to-earth uses Shannon originally had for his work, which began when he was a 22-year-old graduate engineering student at the prestigious Massachusetts Institute of Technology in 1939. He set out with an apparently simple aim: to pin down the precise meaning of the concept of ‘information’.
同义替换：
Shannon initially --- Shannon originally
Intended to achieve --- set out with an apparently simple aim
7.题干：The probe transmitted pictures of both …and …,（C9-T3-R3 Q33）
原文：The space probe, Voyager I, launched in 1977, had sent back spectacular images of Jupiter and Saturn…
同义替换：
The probe --- the space probe
Transmitted --- had sent back
Pictures --- spectacular images of
8.题干：then left the…（C9-T3-R3 Q34）
原文：and then soared out of the Solar System on a one-way mission to the stars.
同义替换：
Left --- soared out of
9.题干：The freezing temperatures were found to have a negative effect on
parts of
the space probe.（C9-T3-R3 Q34-35）
原文：After25 years of exposure to the freezing temperatures of deep space, the probe was beginning to show its age.
同义替换：
Were found --- was beginning to
Have negative effect on --- show its age
The space probe --- the probe
10.题干：Scientists feared that both the …and …were about to stop
working.
（C9-T3-R3 Q35）
原文：Sensors and circuits were on the brink of failing and NASA experts realised that they had to do something or lose contact with their probe forever.
同义替换：
Scientist --- NASA experts
Feared --- realised
Were about to stop working --- were on the brink of failing
11.题干：The only hope was to tell the probe to replace them with…- but
distance made communication with the probe difficult.（C9-T3-R3 Q36）
原文：The solution was to get a message to Voyager I to instruct it to use spares to change the failing parts. With the probe 12 billion kilometres from Earth, this was not an easy task.
同义替换：
The only hope --- the solution
To tell the probe --- to get a message to Voyager I
Replace …with …--- use …to change
Distance --- 12 billion kilometres
Difficult --- not an easy task
12.题干：A …was used to transmit the message at the speed of light.
（C9-T3-R3 Q37）
原文：By means of a radio dish belonging to NASA’s Deep Space Network, the message was sent out into the depths of space. Even travelling at the speed of light, it took over 11 hours to reach its target, far beyond the orbit of Pluto.
同义替换：
A…was used --- by means of a …
To transmit the message --- the message was sent out
At the speed of light --- travelling at the speed of light
13.题干：The message was picked up by the probe and the switchover took
place.（C9-T3-R3 Q37）
原文：Yet, incredibly, the little probe managed to hear the faint call from its home planet, and successfully made the switchover.
同义替换：
Was picked up --- hear the faint call
Took place --- successfully made
14.题干：The concept of describing something as true or false was the starting
point for Shannon in his attempts to send messages over distances.
（C9-T3-R3 Q38）
原文：The most basic form of information, Shannon argued, is whether something is true or false - which can be captured in the binary unit, or ‘bit’, of the form 1 or 0.Having identified this fundamental unit, Shannon set about defining otherwise vague ideas about information and how to transmit it from place to place.
同义替换：
Describing --- having identified
The starting point --- the most basic form
Something as true or false --- something is true or false
Send messages over distances --- transmit it from place to place
15.题干：The amount of information that can be sent in a given time period is
determined with reference to the signal strength and noise level.（C9-T3-R3
Q39）
原文：This rate depends on the relative strengths of the signal and noise travelling down the communication channel, and on its capacity (its ‘bandwidth’).
同义替换：
Is determined with reference to --- depends on
The signal strength and noise level --- the relative strengths of the signal and noise
Be sent --- travelling down
16.题干：Products have now been developed which can convey more
Information than Shannon had anticipated as possible.（C9-T3-R3 Q40）
原文：As recently as 1993, engineers made a major breakthrough by discovering so-called turbo codes - which come very close to Shannon’s ultimate limit for the maximum rate that data can be transmitted reliably, and now play a key role in the mobile videophone revolution.
同义替换：
Products --- the mobile videophone
Been developed --- made a major breakthrough by discovering
Convey more information --- come very close to Shannon’s ultimate limit for the maximum rate
