Question

---How often do I need to feed the dog?
---It___food everyday, or it will be hungry

1. A.
   must give
2. B.
   must be give
3. C.
   must be given
4. D.
   must be gave

Answer 1

C
句意：我需要多久喂一次这条狗？——必须每天喂它，否则它会饿的。结合语境可知下文主语it是动作对象，故用被动语态，选项BD过去分词形式有误，故选C。
考点：被动语态