When we see well, we do not think about our eyes very often．It is only when we cannot see perfectly that we realize how important our eyes are．
People who are near-sighted can only see things that are very close to their eyes．Everything else seems blurry(unclear)．Many people who do a lot of work, such as writing, reading and sewing become near-sighted．
Then People who are far-sighted suffer from just the opposite problem．They can see things that are far away, but they have difficulty in reading a book unless they hold it at arm’s length．If they want to do much reading, they must get glasses, too．
Other people do not see clearly because their eyes are not exactly the right shape．They have what is called astigmatism(散光)．This, too, can be corrected by glasses．Some people’s eyes become cloudy because of cataracts(白内障)．Long ago these people often became blind．Now however, it is possible to operate on the cataracts and remove then．
Having two good eyes is important for judging distances．Each eye sees things from a slightly different angle(角度)．To prove this to yourself, look at an object out of one eye; then look at the same object out of your other eye．You will find the object’s relation to the background and other things around it has changed．The difference between these two different eye views helps us to judge how far away an object is．People who have only one eye cannot judge distance as people with two eyes．
(1)
We should take good care of our eyes．
[ ]
A．
only when we can see well
B．
only when we cannot see perfectly
C．
even if we can see well
D．
only when we realize how important our eyes are
(2)
When things far away seem unclear, one is probably
[ ]
A．
near-sighted
B．
far-sighted
C．
astigmatic
D．
suffering from cataracts
(3)
The underlined word suffer in the third paragraph probably means．
[ ]
A．
experience
B．
imagine
C．
feel pain
D．
are affected with
(4)
Having two eyes instead of one is particularly useful for
[ ]
A．
seeing at night
B．
seeing objects far away
C．
looking over a wide area
D．
judging distances
(5)
People who suffer from astigmatism have．
[ ]
A．
one eye bigger than the other
B．
eyes that are not exactly the right shape
C．
a difficulty that can be corrected by an operation
D．
an eye difficult that cannot be corrected by glasses．
She took up skating at age 85, made her first movie appearance at age 114, and held a concert in the neighborhood on her 121st birthday．
Whe n it comes to long life, Jeanne Calment is the world’s recordholder．She lived to the ripe old age of 122．So is 122 the upper limit to the human life span(寿命)?If scientists come up with some sort of pill or diet that would slow aging, could we possibly make it to 150－or beyond?
Researchers don’t entirely agree on the answers．“Calment lived to 122, so it wouldn’t surprise me if someone alive today reaches 130 or 135,”says Jerry Shay at the University of Texas．
Steve Austad at the University of Texas agrees．“People can live much longer than we think,”he says．“Experts used to say that humans couldn’t live past 110．When Calment blew past that age, they raised the number to 120．So why can’t we go higher?”
The trouble with guessing how old people can live to be is that it’s all just guessing．“Anyone can make up a number,”says Rich Miller at the University of Michigan．“Usually the scientist who picks the highest number gets his name in Time magazine．”
Won’t new anti-aging techniques keep us alive for centuries?Any cure, says Miller, for aging would probably keep most of us kicking until about 120．Researchers are working on treatments that lengthen the life span of mice by 50 percent at most．So, if the average human life span is about 80 years, says Miller,“adding another 50 percent would get you to 120．”
So what can we conclude from this little disagreement among the researchers?That life span is flexible(有弹性的)，but there is a limit, says George Martin of the University of Washington．“We can get flies to live 50 percent longer,”he says．“But a fly’s never going to live 150 years．”
“Of course, if you became a new species(物种)，one that ages at a slower speed, that would be a different story,”he adds．
Does Martin really believe that humans could evolve(进化)their way to longer life?“It’s pretty cool to think about it,”he says with a smile．
(1)
What does the story of Jeanne Calment prove to us?
[ ]
A．
People can live to 122．
B．
Old people are creative．
C．
Women are sporty at 85．
D．
Women live longer than men．
(2)
According to Steve Austad at the University of Texas, ________．
[ ]
A．
the average human life span could be 110
B．
scientists cannot find ways to slow aging
C．
few people can expect to live to over 150
D．
researchers are not sure how long people can live
(3)
Who would agree that a scientist will become famous if he makes the wildest guess at longevity?
[ ]
A．
Jerry Shay．
B．
Steve Austad
C．
Rich Miller
D．
George Martin
(4)
What can we infer from the last three paragraphs?
[ ]
A．
Most of us could be good at sports even at 120．
B．
The average human life span cannot be doubled．
C．
Scientists believe mice are aging at a slower speed than before．
D．
New techniques could be used to change flies into a new species．
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