2. 职称英语
  3. Many years ago people thought the earth was flat. They believed that the sky

Many years ago people thought the earth was flat. They believed that the sky

游客2025-04-15  43
问题     Many years ago people thought the earth was flat. They believed that the sky【C1】______a big upside-down bowl and that the sun, moon, and stars were lamps hanging from the top of the bowl. Later, people【C2】______better. They found out that the earth【C3】______round.
    We call the study of the skies and the planets astronomy, 【C4】______we call the watchers of the skies astronomer. Early astronomers thought the earth was the center of【C5】______They thought the heavens spun【C6】______the earth. Later, they changed their【C7】______. They knew the earth was not the center. They believed that the earth and the【C8】______planets spin around the sun. Today we know this is true.
    Ancient scientists studied the skies【C9】______simple instruments. The first person【C10】______a telescope was named Galileo. In 1610【C11】______four moons around the planet Jupiter. Today【C12】______use more complex equipment. Some of these measure the brightness of light. 【C13】______break lights up into different colors. Radio telescopes make stars and planets【C14】______far closer than Galileo’s telescope could.
    Early astronomers【C15】______five planets in the sky. Besides Earth, they knew about mercury, Venus, Mars, Jupiter, and Saturn. In 1781 a seventh one was discovered and named Uranus. Years later, astronomers found another planet and called it Neptune. The ninth planet to be found is called Pluto. It was not【C16】______until 1930.
    Today scientists can【C17】______almost anywhere. They have reached the heavens with their spacecraft. In 1959, a spacecraft【C18】______took pictures of the dark side of the moon. The years later a spacecraft landed two Americans on the moon. Other important journeys into space【C19】______. Who knows? Maybe【C20】______human beings will live on another planet. Maybe you will be one of them. [br] 【C15】
选项 A、could have seen
B、could see
C、had seen
D、saw
答案 A
解析 空格处对过去的某种状态进行推测。因为在讲述过去的某种状态，用现在完成时即可。因为没有在过去某点说过去保持的某种状态，因此，不使用过去完成时。因为早期天文学家知道包括地球在内的六大行星，因此，他们可能已经观测到了其他五大行星，但没有证据予以证实，因此，用could表示推测，更符合原文意思。因此，A为正确选项。
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