How often:是對(duì)頻率的提問
例如：how often does he purchase
他多久采購一次?
how many times :就是對(duì)次數(shù)進(jìn)行提問：
如：how many times did he purchase in this year?
今年他采購了幾次?
How many times就次數(shù)提問
how often 就頻率提問
how often意為“多久……次、是否經(jīng)?！?用來提問在某一特定的時(shí)間進(jìn)行某個(gè)動(dòng)作的次數(shù),答語通常是always,usually,often,sometimes,once/twice a day/month等.
—How often do you get to school very early?你多久早到校一次?
—Usually.通常.
—How often do you see a film?你多久看一次電影?
—Once a month.每月一次.
其他知識(shí)點(diǎn)
how long,how often,how soon三者都可以譯成“多久”.how long用來提問“多長時(shí)間”,對(duì)“一段時(shí)間的長短”提問時(shí)用,與延續(xù)性動(dòng)詞連用；how often用來提問某動(dòng)作或狀態(tài)發(fā)生的頻率,對(duì)“一段時(shí)間內(nèi)發(fā)生了幾次活動(dòng)”（always,usually,often,never或twice a day等表示頻度的詞或短語）提問時(shí)用；how soon用來提問某人要“多快”能做好某事,或某事要“多快”能完成,對(duì)“過多少時(shí)間（就能……）”（in短語）提問時(shí)用,常用于將來時(shí).而how far意思是“多遠(yuǎn)”,對(duì)距離提問時(shí)用.例如：
How long did you stay there?你在那兒呆多久?
How often do his parents let him watch TV?他父母多久讓他看一次電視?
How soon will her husband come?她丈夫多久會(huì)回來?