Question

—________ have you been reading?

—I've been reading for two hours．

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

Answer 1

C
此题考查对一段时间提问的方式，由答句中for two hours这一表示一段时间的状语可知，用how long提问。A项how soon询问将来时间，意为“多久”；B项how often询问频率，表示“多长时间一次”；D项询问可数名词的数量。