Think of stimulating phrases to which the phrases below are the replies i am afraid not no,you(he,she,they)mustn't

Will you join us today at lunch? - I am afraid not
Must I tell them the whole story? - No, you mustn't
Must she ring when she arrives? - No, she mustn't
Must he bring his bag for checking? - No, he mustn't
Must they take us with them? - No, they mustn't