Question

---_____must I take this medicine every day? 
--- Three times a day

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

Answer 1

B
回答语是每天三次的意思，表示的是频率，对此提问用how often，故选B，how long对长度提问，how far对路程提问，how对方式提问。