文章大意:这是一篇说明文。文章讲述了地球最初形成时期的一些现象及逐渐变化的过程。
1 . No one knows exactly 1 the earth began, as it happened so long ago. 2 , according to a 3 (wide) accepted theory, the universe began with a “Big Bang” that threw matter 4 all directions. After that, atoms began to form and combine to create stars and other bodies.
Water 5 (appear) on other planets like Mars but, unlike the earth, it had disappeared later. 6 was not immediately obvious that water was to be fundamental to the development of life. What many scientists believe is that the continued 7 (present) of water allowed the earth 8 (dissolve) harmful gases and acids into the oceans and seas. This produced 9 chain reaction, 10 made it possible for life to develop.
Water
您最近一年使用:0次