📖 原文
(1) For 150 years scientists have tried to determine the solar constant, the amount of solar (2) energy that reaches the Earth. Yet, even in the most cloud-free regions of the planet, the (3) solar constant cannot be measured precisely. Gas molecules and dust particles in the (4) atmosphere absorb and scatter sunlight and prevent some wavelengths of the light from (5) ever reaching the ground. (6) With the advent of satellites, however, scientists have finally been able to measure the (7) Sun's output without being impeded by the Earth's atmosphere. Solar Max, a satellite (8) from the National Aeronautics and Space Administration (NASA), has been measuring (9) the Sun's output since February 1980. Although a malfunction in the satellite's control (10) system limited its observation for a few years, the satellite was repaired in orbit by (11) astronauts from the space shuttle in 1984. Max's observations indicate that the solar (12) constant is not really constant after all. (13) The satellite's instruments have detected frequent, small variations in the Sun's energy (14) output, generally amounting to no more than 0.05 percent of the Sun's mean energy (15) output and lasting from a few days to a few weeks. Scientists believe these fluctuations (16) coincide with the appearance and disappearance of large groups of sunspots on the (17) Sun's disk. Sunspots are relatively dark regions on the Sun's surface that have strong (18) magnetic fields and a temperature about 2,000 degrees Fahrenheit cooler than the rest (19) of the Sun's surface. Particularly large fluctuations in the solar constant have coincided (20) with sightings of large sunspot groups. In 1980, for example, Solar Max's instruments (21) registered a 0.3 percent drop in the solar energy reaching the Earth. At that time a (22) sunspot group covered about 0.6 percent of the solar disk, an area 20 times larger than (23) the Earth's surface. (24) Long-term variations in the solar constant are more difficult to determine. Although (25) Solar Max's data have indicated a slow and steady decline in the Sun's output, some (26) scientists have thought that the satellite's aging detectors might have become less (27) sensitive over the years, thus falsely indicating a drop in the solar constant. This (28) possibility was dismissed, however, by comparing Solar Max's observations with data (29) from a similar instrument operating on NASA's Nimbus 7 weather satellite since 1978.
❓ 试题解析
问题 29： What does this passage mainly discuss?
A. The launching of a weather satellite
B. The components of the Earth's atmosphere
C. The measurement of variations in the solar constant
D. The interaction of sunlight and air pollution
✅ 正确答案： C）The measurement of variations in the solar constant
📝 解析： 全文讨论太阳常数的测量问题、大气干扰、卫星观测、太阳常数变化。
💡 解题技巧： 主旨题看首段主题句及后文测量发现。
问题 30： Why does the author mention “gas” and “dust” in line 3?
A. They magnify the solar constant.
B. They are found in varying concentrations.
C. Scientific equipment is ruined by gas and dust.
D. They interfere with accurate measurement of the solar constant.
✅ 正确答案： D）They interfere with accurate measurement of the solar constant.
📝 解析： “Gas molecules and dust particles ... absorb and scatter sunlight and prevent ... from ever reaching the ground” — 干扰测量。
💡 解题技巧： 例证题定位干扰原因。
问题 31： Why is it not possible to measure the solar constant accurately without a satellite?
A. The Earth is too far from the Sun.
B. Some areas on Earth receive more solar energy than others.
C. There is not enough sunlight during the day.
D. The Earth's atmosphere interferes with the sunlight.
✅ 正确答案： D）The Earth's atmosphere interferes with the sunlight.
📝 解析： 大气中的气体和尘埃吸收和散射阳光，卫星可避开大气干扰。
💡 解题技巧： 推理题结合第二段“without being impeded by the Earth's atmosphere”。
问题 32： The word “scatter” in line 4 is closest in meaning to
A. emit
B. capture
C. transform
D. disperse
✅ 正确答案： D）disperse
📝 解析： “absorb and scatter sunlight” — scatter = 散射/分散。
💡 解题技巧： 词汇题：scatter = disperse = spread。
问题 33： The word “its” in line 10 refers to the
A. orbit
B. atmosphere
C. satellite
D. malfunction
✅ 正确答案： C）satellite
📝 解析： “a malfunction in the satellite's control system limited its observation” — its 指 satellite's。
💡 解题技巧： 代词题找前一个名词。
问题 34： The word “detected” in line 13 is closest in meaning to
A. estimated
B. disregarded
<>C. registered
D. predicted
✅ 正确答案： C）registered
📝 解析： “The satellite's instruments have detected frequent, small variations” — detected = 探测到/记录到。
💡 解题技巧： 词汇题：detect = register = observe。
问题 35： According to the passage, scientists believe variations in the solar constant are related to
A. sunspot activity
B. unusual weather patterns
C. increased levels of dust
D. fluctuations in the Earth's temperature
✅ 正确答案： A）sunspot activity
📝 解析： “Scientists believe these fluctuations coincide with the appearance and disappearance of large groups of sunspots”。
💡 解题技巧： 因果细节题定位“coincide with”。
问题 36： The word “decline” in line 25 is closest in meaning to
A. fall
B. reversal
C. release
D. fluctuation
✅ 正确答案： A）fall
📝 解析： “a slow and steady decline in the Sun's output” — decline = 下降。
💡 解题技巧： 词汇题：decline = decrease = fall。
问题 37： Why did scientists think that Solar Max might be giving unreliable information?
A. Solar Max did not work for the first few years.
B. The space shuttle could not fix Solar Max's instruments.
C. Solar Max's instruments were getting old.
D. Nimbus 7 interfered with Solar Max's detectors.
✅ 正确答案： C）Solar Max's instruments were getting old.
📝 解析： “the satellite's aging detectors might have become less sensitive over the years”。
💡 解题技巧： 细节题定位“aging detectors”。
问题 38： The phrase “This possibility” in lines 27-28 refers to the likelihood that the
A. solar constant has declined
B. Nimbus 7 satellite is older than Solar Max
C. solar constant cannot be measured
D. instruments are providing inaccurate data
✅ 正确答案： D）instruments are providing inaccurate data
📝 解析： “This possibility was dismissed” — 指前文“aging detectors might have become less sensitive, thus falsely indicating a drop”。
💡 解题技巧： 指代题找前文提出的可能性。
问题 39： The attempt to describe the solar constant can best be described as
A. an ongoing research effort
B. an issue that has been resolved
C. a question that can never be answered
D. historically interesting, but irrelevant to contemporary concerns
✅ 正确答案： A）an ongoing research effort
📝 解析： 太阳常数测量持续150年，现在仍在进行，并发现它并非恒定。
💡 解题技巧： 推理题结合时间跨度和持续研究。
🌐 中文翻译
150年来，科学家一直试图确定太阳常数——到达地球的太阳能量的数量。然而，即使在地球上最无云的区域，太阳常数也无法精确测量。大气中的气体分子和尘埃颗粒吸收和散射阳光，并阻止某些波长的光 ever reaching 地面。 然而，随着卫星的出现，科学家终于能够不受地球大气层阻碍地测量太阳的输出。Solar Max 是一颗来自 NASA（美国国家航空航天局）的卫星，自1980年2月以来一直在测量太阳的输出。尽管卫星控制系统的一个 malfunction 使其观测受限了几年，但该卫星于1984年由宇航员从航天飞机上在轨道上修复。Max 的观测表明，太阳常数毕竟不是真的 constant。 该卫星的仪器探测到太阳能量输出中频繁的微小变化，通常不超过太阳平均能量输出的0.05%，持续几天到几周。科学家认为这些波动与太阳圆盘上 large groups of sunspots 的出现和消失同时发生。太阳黑子是太阳表面相对较暗的区域，具有强磁场，温度比太阳表面其他部分低约2000华氏度。太阳常数中特别大的波动 coinciding with 大型太阳黑子群的 sightings。例如，1980年，Solar Max 的仪器记录到达地球的太阳能下降了0.3%。当时一个太阳黑子群覆盖了太阳圆盘的约0.6%，相当于20倍于地球表面的面积。 太阳常数的长期变化更难以确定。尽管 Solar Max 的数据显示太阳输出缓慢而稳定的 decline，但一些 scientists 认为卫星 aging detectors 多年来可能变得不那么敏感，从而错误地指示太阳常数的下降。然而，通过将 Solar Max 的观测结果与自1978年以来在 NASA 的 Nimbus 7 气象卫星上运行的类似仪器的数据进行比较，这种可能性被 dismissed 了。
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