根据短文理解，从A、B、C、D四个选项中选择最佳答案填空。

    When you look up into the sky on a 1  night, you will see the moon and the  2.

    Since ancient times, men 3  wanted to know more about the moon, the stars and other  4 in the sky. They invented telescopes to get a closer look at them and 5 that there are many suns. moons and planets in the sky. They became interested in the    6 .

  7  October 4th, 1957, the Space Age began when the first man-made satellite was sent into space  8the earth. Today, scientists are able to 9 on the moon. Man will  10  more places one day.

学习了凸透镜成像规律后，某同学要探究“凸透镜成实像时，像距与物距的关系”．实验中，应使物距____（选填“小于”、“等于”或“大于”）焦距．该实验至少应收集____组数据．