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What made this eclipse so unique?
What made this eclipse so unique?
admin
2012-04-23
64
问题
What made this eclipse so unique?
On December 25, 2000, many people across North America received a rare Christmas treat when the moon passed in front of the sun resulting in a partial solar eclipse.
Solar eclipses occur when the moon passes between the earth and the sun, and the moon’s shadow covers part of the earth, and a total solar eclipse takes place when the moon’s shadow blocks out the sun entirely. What made this particular solar eclipse unique was that such an event has occured on December twenty - fifth only 30 times during the past 5000 years, the last time in 1954. But people must be exceptionally careful when attempting to view a solar eclipse. Without taking precautionary measures, one can permanently damage the retina of the eyes; however, there are several safe methods of witnessing this heavenly marvel.
First, you can view a solar eclipse by using eclipse safety glasses for filtering out the sun’s harmful rays. They should be used when any part of the sun is visible. Sunglasses can block out some of the sun’s ultraviolet rays, but the results can be very deceptive. The eye’s natural reaction to this darken state when wearing sunglasses is to make the pupil larger, which allows in more light and can intensify the damage to your eyes. You can also watch an eclipse by projecting the sun’s image on a piece of paper either by using a telescope, or easier yet, by creating a pinhole in a piece of paper and viewing the result on another piece of paper, thus called a pinhole projector.
Only during a total eclipse when the sun is completely and briefly covered can you watch the eclipse without eye protection. Even then, extreme caution should be taken. In case you didn’t catch this last spectacular eclipse on December twenty - fifth, 2000, there’s no need to fret. Your posterity can record the next eclipse on Christmas in the year 2307, but only if their visiting the west coast of Africa for the holidays.
选项
A、Sunglasses block out only a limited amount of the sun’s ultraviolet rays that can damage the eye.
B、Sunglasses can only filter harmful rays during total solar eclipses at their greatest magnitude.
C、Sunglasses tend to cause the center of the eye to enlarge allowing in more intense light.
D、Sunglasses should be used when any part of the sun is visibl
答案
B
解析
对于如何观看日食,报道中提出的第一种办法就是用太阳镜过滤太阳的有害光线,但同时也指出太阳镜也有它的问题:They should be used when any part of the sun is visible. Sunglasses can block out some of the sun’s ultraviolet rays, but the results can be very deceptive. The eye’s natural reaction to this darken state when wearing sunglasses is to make the pupil larger, which allows in more light and can intensify the damage to your eyes.这三句恰好与D、A、C选项中的内容相符合,报道中并没有提到过B项,故正确答案应为B。
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