don't you think it's time we get down to business 为什么句型是it's time do sth.

don't you think it's time we get down to business 为什么句型是it's time do sth.
get down to 在这里是开始认真处理，着手做的意思....
business不是do sth.
呃真的有it's time (for) sb.do sth.这个句型吗？
that那个比较可信~