how often的意思是多久，主要用來(lái)提問(wèn)“多長(zhǎng)時(shí)間”，下面我們來(lái)看一下具體的用法。

主要用來(lái)問(wèn)頻率的。比如：How often do you take exercises?你多久鍛煉一次？twice a week.我一周鍛煉兩次.I take exercises every day，我每天都鍛煉身體.

用來(lái)提問(wèn)某動(dòng)作或者狀態(tài)發(fā)生的頻率，指的是“一段時(shí)間內(nèi)發(fā)生了幾次活動(dòng)”。How often do your parents let you to watch TV.你的父母多久讓你看一次電視？

注意和how soon,how long的區(qū)別，how soon主要是對(duì)“多快，多久”提問(wèn)？How soon will you come back？how long是就"一段時(shí)間"提問(wèn)的，how long have you lived here?

注意和how far的區(qū)別，how far主要是就"距離"提問(wèn)的，how far can you throw the ball?