首先我们来看下how far和how long的大致意思：
how far：词性为短语，how far是一个用于询问距离的短语，常用于对两个地点之间的距离进行提问。
how long：词性为短语，how long是一个用于询问时间长度的短语，常用于询问一个行动、事件或过程的持续时间。
通过下面的表格我们了解下how far和how long的含义、发音和用法
接下来让我们看下how far和how long的用法区别：
1.词性：how far是短语，how long也是短语，但词性不同
例子：
-How far is it from here to the nearest supermarket?
(How far is it from here to the nearest supermarket?)
-How long does it take to finish the project?
(How long does it take to finish the project?)
2.含义：how far用于询问距离，how long用于询问时间长度
例子：
-How far is the nearest gas station?
(How far is the nearest gas station?)
-How long have you been studying English?
(How long have you been studying English?)
3.用法简介：how far通常用于询问两个地点之间的距离，how long通常用于询问一个行动、事件或过程的持续时间
例子：
-How far is it from here to the airport?
(How far is it from here to the airport?)
-How long does it usually take to cook dinner?
(How long does it usually take to cook dinner?)
4.发音：how far的英式发音为haʊ fɑː(r)，美式发音为haʊ fɑːr；how long的英式发音为haʊ lɒŋ，美式发音为haʊ lɔːŋ
例子：
-How far is the train station from here?
(How far is the train station from here?)
-How long is the movie?
(How long is the movie?)