句型转换。 1. My brother is a police officer . (就划线部分提问) ____________________________________________________________? 2. What is your mother? (写出回答) _____________ _____________ a teacher. 3. His brother goes to work on foot . (就划线部分提问) ____________________________________________________________? 4. Is your mother a waitress? (肯定回答、否定回答) Yes, _____________ _____________. No, _____________ _____________.