I must fax you must fax she must fax we must fax you must fax they must fax
V-ing form
I must be faxing you must be faxing she must be faxing we must be faxing you must be faxing they must be faxing
Perfect
I must have faxed you must have faxed she must have faxed we must have faxed you must have faxed they must have faxed
V-ing perfect
I must have been faxing you must have been faxing she must have been faxing we must have been faxing you must have been faxing they must have been faxing
Negation
Simple form
I mustn't fax you mustn't fax she mustn't fax we mustn't fax you mustn't fax they mustn't fax
V-ing form
I mustn't be faxing you mustn't be faxing she mustn't be faxing we mustn't be faxing you mustn't be faxing they mustn't be faxing
Perfect
I mustn't have faxed you mustn't have faxed she mustn't have faxed we mustn't have faxed you mustn't have faxed they mustn't have faxed
V-ing perfect
I mustn't have been faxing you mustn't have been faxing she mustn't have been faxing we mustn't have been faxing you mustn't have been faxing they mustn't have been faxing
Interrogative form
Simple form
must I fax? must you fax? must she fax? must we fax? must you fax? must they fax?
V-ing form
must I be faxing? must you be faxing? must she be faxing? must we be faxing? must you be faxing? must they be faxing?
Perfect
must I have faxed? must you have faxed? must she have faxed? must we have faxed? must you have faxed? must they have faxed?
V-ing perfect
must I have been faxing? must you have been faxing? must she have been faxing? must we have been faxing? must you have been faxing? must they have been faxing?
Interro-negative form
Simple form
mustn't I fax? mustn't you fax? mustn't she fax? mustn't we fax? mustn't you fax? mustn't they fax?
V-ing form
mustn't I be faxing? mustn't you be faxing? mustn't she be faxing? mustn't we be faxing? mustn't you be faxing? mustn't they be faxing?
Perfect
mustn't I have faxed? mustn't you have faxed? mustn't she have faxed? mustn't we have faxed? mustn't you have faxed? mustn't they have faxed?
V-ing perfect
mustn't I have been faxing? mustn't you have been faxing? mustn't she have been faxing? mustn't we have been faxing? mustn't you have been faxing? mustn't they have been faxing?