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 must not gather you must not gather he must not gather we must not gather you must not gather they must not gather
V-ing form
I must not be gathering you must not be gathering he must not be gathering we must not be gathering you must not be gathering they must not be gathering
Perfect
I must not have gathered you must not have gathered he must not have gathered we must not have gathered you must not have gathered they must not have gathered
V-ing perfect
I must not have been gathering you must not have been gathering he must not have been gathering we must not have been gathering you must not have been gathering they must not 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
must I not gather? must you not gather? must he not gather? must we not gather? must you not gather? must they not gather?
V-ing form
must I not be gathering? must you not be gathering? must he not be gathering? must we not be gathering? must you not be gathering? must they not be gathering?
Perfect
must I not have gathered? must you not have gathered? must he not have gathered? must we not have gathered? must you not have gathered? must they not have gathered?
V-ing perfect
must I not have been gathering? must you not have been gathering? must he not have been gathering? must we not have been gathering? must you not have been gathering? must they not have been gathering?