---- Be careful,          you will make mistakes in your exams.

---- I know that, Mum. One can never be too careful.

A. and             B. or                    C. nor            D. but

---Be careful ,________you will make mistakes in your exams.

---I know that，Mum. One can never be too careful.

1. A.
   and
2. B.
   or
3. C.
   nor
4. D.
   but

---Be careful ,     you will make mistakes in your exams. 
---I know that，Mum. One can never be too careful

1. A.
   and
2. B.
   or
3. C.
   nor
4. D.
   but