( )21. You can _______ a conversation(对话) with you partner to practice English.
A. pick up B. make up C. look up D. catch up
( )22. It's not good to ask questions about someone's _______ life.
A. busy B. simple C. personal D. healthy
( )23. He knocked on the door, but _______ answered.
A. somebody B. anybody C. nobody D. everybody
