is known to everybody, the moon travels around the earth once every month． [ ] A

本题考查as引导非限定性定语从句。as引导从句的意思是“正如……”，其位置可以是句首也可以是句末。当as在从句中充当主语时，常用下面的结构：as is know, as is said, as is reported等，所以本题的答案是B项。