Here are the correct answers for the questions you provided:
Question 7: Actions speak louder than words.
Question 8: The papers haven't been signed.
Question 9: His father's voice sounded stronger than I thought.
Question 10: Mike is a careless driver, he drives worse than you.
Question 11: Kate is the best dancer in our class.
Question 12: Miss Bennet has been told about the party.
Question 13: She is twice as lively as her sister.
Question 14: Why is the music so loud?
Question 15: I earn less money than he does.
Good luck with your studies!