how far意思是“多远”，表达的是从某地到某地的距离（多远）。
如：How far is it from your home to your company? 你家离公司有多远？
how long意思是“多长时间”。通常用来询问动作在时间上持续的长度。
如：How long have you been in London? 你在伦敦待了多久？
Example: How far is our school from your home? 从你家到咱们学校有多远？
Example: How far is it from Australia to New Zealand? 从澳大利亚到新西兰有多远？
Example: How long did your sister stay in Beijing? 你妹妹在北京待了多久？
Example: How long did you wait for her here? 你在这等了她多久？
