Question

---It is rather cold here．Shall we light a fire?

---No, we ______．Things here are easy to catch fire．

1. A.
   won’t
2. B.
   may not
3. C.
   mustn’t
4. D.
   needn’t

Answer 1

C
mustn’t表示一般陈述句的否定形式，意思为“不许，不让，禁止”；因为有提示：Things here are easy to catch fire．所以用mustn’t。