I must gather you must gather he must gather we must gather you must gather they must gather
V-ing form
I must be gathering you must be gathering he must be gathering we must be gathering you must be gathering they must be gathering
Perfect
I must have gathered you must have gathered he must have gathered we must have gathered you must have gathered they must have gathered
V-ing perfect
I must have been gathering you must have been gathering he must have been gathering we must have been gathering you must have been gathering they must have been gathering
Negation
Simple form
I mustn't gather you mustn't gather he mustn't gather we mustn't gather you mustn't gather they mustn't gather
V-ing form
I mustn't be gathering you mustn't be gathering he mustn't be gathering we mustn't be gathering you mustn't be gathering they mustn't be gathering
Perfect
I mustn't have gathered you mustn't have gathered he mustn't have gathered we mustn't have gathered you mustn't have gathered they mustn't have gathered
V-ing perfect
I mustn't have been gathering you mustn't have been gathering he mustn't have been gathering we mustn't have been gathering you mustn't have been gathering they mustn't have been gathering
Interrogative form
Simple form
must I gather? must you gather? must he gather? must we gather? must you gather? must they gather?
V-ing form
must I be gathering? must you be gathering? must he be gathering? must we be gathering? must you be gathering? must they be gathering?
Perfect
must I have gathered? must you have gathered? must he have gathered? must we have gathered? must you have gathered? must they have gathered?
V-ing perfect
must I have been gathering? must you have been gathering? must he have been gathering? must we have been gathering? must you have been gathering? must they have been gathering?
Interro-negative form
Simple form
mustn't I gather? mustn't you gather? mustn't he gather? mustn't we gather? mustn't you gather? mustn't they gather?
V-ing form
mustn't I be gathering? mustn't you be gathering? mustn't he be gathering? mustn't we be gathering? mustn't you be gathering? mustn't they be gathering?
Perfect
mustn't I have gathered? mustn't you have gathered? mustn't he have gathered? mustn't we have gathered? mustn't you have gathered? mustn't they have gathered?
V-ing perfect
mustn't I have been gathering? mustn't you have been gathering? mustn't he have been gathering? mustn't we have been gathering? mustn't you have been gathering? mustn't they have been gathering?