20- "Have you ever been to London?" No, I haven't.
21- "Has Jenny read that detective story yet?" Yes, she has.
22 - Sorry, I can't meet you today, I haven't done my homework yet.
23 - "Don't eat food in class!" said the teacher.
24 - "Clean up your room!" said my mother.
25 - Please Dad, don't tell me that story about your childhood again.