它的关键句是什么.　　A man has a bird.It is very clever.Every day the

它的关键句是什么.
　　A man has a bird.It is very clever.Every day the man speaks to the bird.“Hello!”he says.“Hello!”the bird answers.“What are you doing?”says the man.“What are you doing?”says the bird.
　　The man is not at home one day.A thief comes in.He is taking many things.“Hello!”The thief hears the bird's words.“What are you doing?”The thief is very afraid,so he does not take any things and runs out of the house.