单选题
It was not "the comet of the century" experts predicted
it might be. However, Kohoutek has pro- vided a bonanza of scientific
information. It was first spotted 370 million miles from Earth, by an astronomer
who was searching the sky for asteroids, and after whom the comet was named.
Scientists who tracked Kohoutek the ten months before it passed the Earth
predicted the comet would be a brilliant spectacle. But Kohoutek fell short of
these predictions, disappointing millions of amateur sky watchers, when it
proved too pale to be seen with the unaided eye. Researchers were very happy
nonetheless With the new information they were able to glean from their
investigation of the comet. Perhaps the most significant discovery was the
identification of two important chemical compounds — methyl cyanide and hydrogen
cyanide — never before seen in comets, but found it the far reaches of
interstellar space. This discovery revealed new clues about the origin of
comets. Most astronomers agree that comets are primordial remnants from the
formation of the solar system, but whether they were born between Jupiter and
Neptune or much farther out toward interstellar space has been the subject of
:much debate. If compounds no more complex than ammonia and methane, key
components of Jupiter, were seen in comets, it would suggest that comets form
within the planetary orbits. But more complex compounds, such as the methyl
cyanide found in Kohoutek, point to formation far beyond the planets; there the
deep freeze of space has kept them unchanged.
单选题
Why was Kohoutek referred to as" the comet of the century"?
A. It was thought to be extremely old.
B. It passes the Earth once a century.
C. Scientists predicted it would be very bright.
D. Scientists have been tracking it for a century.
【正确答案】
B
【答案解析】[解析] 世纪慧星指慧星一个世纪才经过地球一回。故应选B。
单选题
In what respect was Kohoutek a disappointment?
A. It could be seen only through special equipment.
B. It did not approach the Earth.
C. It did not provide valuable scientific information.
D. It was moving too rapidly for scientists to photograph.
【正确答案】
A
【答案解析】[解析] 文章里说到，预测结果是慧星的到来会是“brilliant spectacle”光耀夺目的壮观，而实际上too pale to be seen with the unaided eye。故应选A。
单选题
According to the passage, what is one major component of Jupiter?
A. Hydrogen cyanide.
B. Methyl cyanide.
C. Hydrogen.
D. Ammonia.
【正确答案】
D
【答案解析】[解析] 文章倒数第四行：If compounds no more complex than ammonia and methane，key components of Jupiter，were seen in comets．如果混合物只是氮和甲烷，那么在慧星上发现木星的主要元素是氮和甲烷。故应选D。
单选题
Which of the following questions is best answered by information gained
from Kohoutek?
A. Where were comets formed?
B. When were comets formed?
C. Where was the solar system formed?
D. How was the solar system formed?
【正确答案】
A
【答案解析】[解析] 从 kohoutek 得出的信息证明了慧星在哪儿形成的。文章第九行：This discovery revealed new clues about the origin of comets。故应选A。