often的用法：一般用于动词之前, be 和助动词之后, 有时也用于句末以加强语气。
He is often late for school.
He often goes to school by bike.
My father very often goes to Beijing on business.
Very often my father goes to Beijing on business.
My father goes to Beijing on business very often.
as often as 每当
as often as not (=more often than not) 多次, 屡次, 往往
every so often 偶尔, 有时
once too often 又一次, 再一次, 次数太多
often and often 屡次三番, 经常