有一种白色粉末由等质量的两种物质混合而成，分别取适量该白色粉末置于三支试管中进行实验。

①逐滴加入6 mol·L^－1盐酸，同时不断振荡试管，有气泡产生，反应结束后得到无色透明溶液

②加热试管中的白色粉末，试管口有水滴凝结

③逐滴加入6 mol·L^－1硫酸，同时不断振荡试管，有气泡产生，反应结束后试管中还有白

色不溶物

下列混合物中符合以上实验现象的是                                      (　　)

求证：DE=BF．

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.

两个比的比值都是5，比例的各项都是整数．