9．
46．What can we learn from the answer to the first question？B
A．Some equipment is able to read human minds．
B．Some progress has been made in mind reading．
C．Test subjects have been used to make decisions．
D．Computer programs can copy brain processes．
47．People laugh when tickled by others because the feeling isA．
A．unexpected
B．expected
C．comfortable
D．uncomfortable
48．Who has got a little child according to the text？B
A．Ms．Leon
B．Mr．Lewis
C．Mr．Moeller
D．Dr．Jeffers
49．According to the text，Jeffers is probablyC．
A．a computer programmer
B．a test subject
C．a human brain expert
D．a medical doctor．
| Ask Dr？Jeffers | This month Dr．Jeffers is answering questions about the human brain and how it works． |
| Dear Dr．Jeffers， One of my colleagues，Felix Moeller，told me that scientists are learning to use computer to‘read minds'．Is there any truth to this story/ -Jane Leon，New York，USA Dear Ms．Leon， Well，a lot of research is being conducted in this area，but so far，the brain scanning equipment and corresponding computer programs haven't been able to actually read thoughts．In one experiment，tes t subjects（受试者）were connected to scanning equipment and shown two numbers on a screen．They were then asked to choose between adding or subtra cting（减）the two numbers．Using this method，researchers were able to follow brain processes and make the correct assumptions（假设）70 percent of the time．It's not quite mind reading，but it's certainly a first step． -Dr．J． | |
| Dear Dr．Jeffers， My three-year-old son loves it when I dig my fingers into his sides and tickle （胳肢）him until he laughs uncontrollably．The other day I noticed him trying to tickle himself but he couldn't do it．Why not？ -Glenn Lewis，Vancouver，Canada Dear Mr．Lewis， It's because of how the brain works．The brain is trained to know what to pay attention to and what to ignore．It causes us to ignore physical feelings we expect to happen，but it causes a mild panic reaction when there is an unexpected feeling．For example，you don't notice how your shoulder feels while you're walking down the street．But if someone comes up behind you and touches you lightly on the shoulder，you may jump in fear．It's that unexpected part that causes the tickle reaction． -Dr．J． | |
A．Some equipment is able to read human minds．
B．Some progress has been made in mind reading．
C．Test subjects have been used to make decisions．
D．Computer programs can copy brain processes．
47．People laugh when tickled by others because the feeling isA．
A．unexpected
B．expected
C．comfortable
D．uncomfortable
48．Who has got a little child according to the text？B
A．Ms．Leon
B．Mr．Lewis
C．Mr．Moeller
D．Dr．Jeffers
49．According to the text，Jeffers is probablyC．
A．a computer programmer
B．a test subject
C．a human brain expert
D．a medical doctor．
1．For more than twenty years scientists have been seeking to understand the mystery of the‘‘sixth sense"of direction．By trying out ideas and solving problems one by one，they are now getting closer to one answer．
One funny idea is that animals might have a built-in compass（指南针）．
Our earth itself is a big magnet（磁体）．So a little magnetic needle that swings freely lines itself with the big earth magnet to point north and south．When people discovered that idea about athousand years ago and invented the compass，it allowed sailors to navigate （航海）on oceanvoyages，even under cloudy skies．
Actuallly the idea of the living compass came just from observing animals in nature．
Many birds migrate twice a year between their summer homes and winter homes．Some of them fly for thousands of kilometers and mostly at night．Experiments have shown that some birds can recognize star patterns．But they can keep on course even under cloudy skies．How can they do that？
A common bird that does not migrate but is great at finding its way home is the homing pigeon．Not all pigeons can find their way home．Those that can are very good at it，and they have been widely studied．
One interesting experiment was to attach little magnets to the birds'heads to block their magnetic sense-just as a loud radio can keep you from hearing a call to dinner．On sunny days，that did not fool the pigeons．Evidently they can use the sun to tell which way they are going．But on cloudy days，the pigeons with magnets could not find their way．It was as if the magnets had blocked their magnetic sense．
Similar experiments with the same kind of results were done with honeybees．These insects also seem to have a special sense ot direction．
In spite of the experiments，the idea of an animal compass seemed pretty extraordinary．How would an animal get the magnetic stuff for a compass．
An answer came from an unexpected source．A scientist was studying bacteria that live in the mud of ponds and marshes．He found accidentally little rod-like bacteria that all swam together in one direction-north．
Further study showed that each little bacterium had a chain of dense particles inside，which proved magnetic．The bacteria had made themselves into little magnets that could line up with the earth's magnet．
The big news was that a living thing，even a simple bacterium，can make magnetite．That led to a search to see whether animals might have it..By using a special instrument called magnetometer，scientists were able to find magnetite in bees and birds，and even in fish．In each animal，except for the bee．the magnetic stuff was always in or closer to the brain．
Thus the idea of a built-in animal compass began to seem reasonable．
One funny idea is that animals might have a built-in compass（指南针）．
Our earth itself is a big magnet（磁体）．So a little magnetic needle that swings freely lines itself with the big earth magnet to point north and south．When people discovered that idea about athousand years ago and invented the compass，it allowed sailors to navigate （航海）on oceanvoyages，even under cloudy skies．
Actuallly the idea of the living compass came just from observing animals in nature．
Many birds migrate twice a year between their summer homes and winter homes．Some of them fly for thousands of kilometers and mostly at night．Experiments have shown that some birds can recognize star patterns．But they can keep on course even under cloudy skies．How can they do that？
A common bird that does not migrate but is great at finding its way home is the homing pigeon．Not all pigeons can find their way home．Those that can are very good at it，and they have been widely studied．
One interesting experiment was to attach little magnets to the birds'heads to block their magnetic sense-just as a loud radio can keep you from hearing a call to dinner．On sunny days，that did not fool the pigeons．Evidently they can use the sun to tell which way they are going．But on cloudy days，the pigeons with magnets could not find their way．It was as if the magnets had blocked their magnetic sense．
Similar experiments with the same kind of results were done with honeybees．These insects also seem to have a special sense ot direction．
In spite of the experiments，the idea of an animal compass seemed pretty extraordinary．How would an animal get the magnetic stuff for a compass．
An answer came from an unexpected source．A scientist was studying bacteria that live in the mud of ponds and marshes．He found accidentally little rod-like bacteria that all swam together in one direction-north．
Further study showed that each little bacterium had a chain of dense particles inside，which proved magnetic．The bacteria had made themselves into little magnets that could line up with the earth's magnet．
The big news was that a living thing，even a simple bacterium，can make magnetite．That led to a search to see whether animals might have it..By using a special instrument called magnetometer，scientists were able to find magnetite in bees and birds，and even in fish．In each animal，except for the bee．the magnetic stuff was always in or closer to the brain．
Thus the idea of a built-in animal compass began to seem reasonable．
| The Magnetic Sense-The Living Compass | |
| Passage outline | Supporting details |
| The existence of the earth magnet and the invention of the navigating compass | ◇Our earth is a big magnet and a little freely （71）swinging magnetic needle lines itself with the earth magnet to point north and south． ◇（72）Basedon the idea above，the navigating compass was invented． |
| The possibility of birds'built-in compasses | ◇One piece of evidence is the （73）migrationof many birds between their summer homes and winter homes． ◇Birds can recognize star patterns on clear nights and keep on course （74）even under cloudy skies |
| The （75）experiments/tests/study/research on pigeons'and bees'built-in compasses | ◇Little magnets were tied to the pigeons'heads to （76）block their magnetic sense． ◇The pigeons'magnetic sense seemed to be affected on （77）cloudydays． ◇Similar things with the same results were done with bees． |
| The （78）discovery of the magnetic stuff for the animal compass | ◇Little rod-like bacteria were found by chance to swim together in the direction of （79）north． ◇Some animals had a chain of dense magnetic particles in or close to the （80）brain（s） inside their bodies． |
13．Knowledge begins to increase as soon as one individual communicates his ideas to _______ by means of speech．（ ）
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| A． | other | B． | another | C． | the other | D． | some other |