1. how long“多长”，询问动作在时间上所持续的长度。其答语部分或划线部分可能是：

1）“for + 时间段”，有时可能没有介词for。如：

---How long did he wait for you here？他在这儿等了你多久？

--- For two hours. 两个小时。

It took him 20 minutes to finish his homework. (对话线部分提问)

→How long did it take him to finish his homework?

2）“since + 具体时间”，“since + 时间段 + ago”或者“since + 从句”。如：

---How long are you feeling like this? 像这样已经多久了？

---Since last night.从昨晚到现在。

3）表示时间的between…and…,from…to…等介词短语。如：

They were playing football from 9:00 to 10:00 yesterday. (对话线部分提问)

→How long were they playing football yesterday?

另外，how long也可以询问某事物的具体长度。如：

---How long is the desk？这张桌子有多长？

---1.2 meters. 1.2米。

2. how far“多远”，询问路程、距离。如：

How far is it from here to school? 从这儿到学校有多远