as often as 每当……
例As often as I saw him ,I saw him grow taller.
每次我看到他,他都又长高了.
2.as often as not=more often than not往往,常常,大半
3.every so often有时,偶尔
4.how often
often的意思：
1.常常,经常,时常 many times; at short intervals; frequently
2.在大多数情况下 in many instances