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One of the most breathtaking natural occurrences is the northern lights or aurora borealis. When it occurs.in the southern hemisphere, it is called the southern lights. The northern lights can be viewed by many more people,especially those who live close to the North Pole in Europe and Canada. This phenomenon, which is dazzling display of green, red and blue lights that shoot across the sky,is caused by atoms that emit light. These atoms are in the earth’s upper atmosphere. They get hit by subatomic particles that are emitted by the sun and the collisions cause light emissions. These particles travel though space and hit the earths magnetic field, where most of them are repelled. However, a few get through into the atmosphere, and cause the northern and southern lights. No one who has seen these lights forgets them, for they are bright, fast moving, unpredictable and thrilling.
It's like watching a giant hand wave a paintbrush across the sky, erase its work, and swiftly paint again.
【題組】24. What happens to the sun’s subatomic particles when they approach
(A) They are absorbed into the atmosphere.
(B) They are mostly deflected by the magnetic field but some get into the atmosphere.
(C) They are all deflected by the magnetic field.
(D) They go straight through the atmosphere and hit the earth.
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