Question

—Kate, do you know ___it is from here to the post office?

—About twenty minutes’ walk.

1. A.
   how long
2. B.
   how often
3. C.
   how far
4. D.
   how soon

Answer 1

C
About twenty minutes’ walk意思是20分钟的路程，表示的是距离故用how far来提问。