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 must not gather you must not gather she 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 she 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 she 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 she 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 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
must I not gather? must you not gather? must she 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 she 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 she 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 she not have been gathering? must we not have been gathering? must you not have been gathering? must they not have been gathering?