According to ________ widely accepted theory, ________ universe began with ________ Big Bang that threw matter in all directions．

A．a; the; a

B．a; the;/

C．the; an; a

D．the;/; a

阅读下面的短文，在标有序号的空白处填入一个适当的词，或填入括号中动词的适当形式。

No one knows 　　1　　 how the earth began, as it happened so long ago．However, according to a widely 　　2　　(accept)theory, the universe began with a “Big Bang”　　3　　 threw matter in all directions．　　4　　 several billion years afterwards, the earth was still just a cloud of dust．What it was to become was uncertain until between 4.5 and 3.8 billion years ago 　　5　　 the dust settled into a solid 　　6　　．The earth became 　　7　　 violent that it was not clear whether the shape would last or not．It exploded loudly with fire and rock．They were 　　8　　 time to produce carbon, nitrogen, water vapor and other gases, which were 　　9　　(make)the earth’s atmosphere．What is even more important is that as the earth cooled down, water began to appear on its 　　10　　．