—By the way is it from your home to the Summer Palace?—It usually takes me 30 minutes to

问题补充：

—By the way, is it from your home to the Summer Palace?

—It usually takes me 30 minutes to walk there.

A. How long

B. How far

C. How soon

D. How often

答案：

A. How long

(答案→)B. How far

C. How soon

D. How often

解析：句意：顺便问，从你家到颐和园有多远？步行到那里通常要花我30分钟。How long 多久，对一段时间提问； How far多远，对距离提问； How soon多久以后； How often多久一次。根据答语可知该选B。