I must gather you must gather she must gather we must gather you must gather they must gather
V-ing form
I must be gathering you must be gathering she must be gathering we must be gathering you must be gathering they must be gathering
Perfect
I must have gathered you must have gathered she 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 she 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 she 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 she 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 she 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 she 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 she gather? must we gather? must you gather? must they gather?
V-ing form
must I be gathering? must you be gathering? must she be gathering? must we be gathering? must you be gathering? must they be gathering?
Perfect
must I have gathered? must you have gathered? must she 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 she 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 she 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 she 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 she 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 she have been gathering? mustn't we have been gathering? mustn't you have been gathering? mustn't they have been gathering?