You mustn't/don't have to open the door for a stranger. A stranger may/should trick you. You have to/might answer the

1) You mustn\'t open the door for a stranger. 2) A stranger may trick you. 3) You might answer the phone. 4) You don\'t have to tell everybody that you are home alone. 5) You must know your parents\' phone number. 6) It must be wise to know your neighbours.