I must sip you must sip she must sip we must sip you must sip they must sip
V-ing form
I must be sipping you must be sipping she must be sipping we must be sipping you must be sipping they must be sipping
Perfect
I must have sipped you must have sipped she must have sipped we must have sipped you must have sipped they must have sipped
V-ing perfect
I must have been sipping you must have been sipping she must have been sipping we must have been sipping you must have been sipping they must have been sipping
Negation
Simple form
I must not sip you must not sip she must not sip we must not sip you must not sip they must not sip
V-ing form
I must not be sipping you must not be sipping she must not be sipping we must not be sipping you must not be sipping they must not be sipping
Perfect
I must not have sipped you must not have sipped she must not have sipped we must not have sipped you must not have sipped they must not have sipped
V-ing perfect
I must not have been sipping you must not have been sipping she must not have been sipping we must not have been sipping you must not have been sipping they must not have been sipping
Interrogative form
Simple form
must I sip? must you sip? must she sip? must we sip? must you sip? must they sip?
V-ing form
must I be sipping? must you be sipping? must she be sipping? must we be sipping? must you be sipping? must they be sipping?
Perfect
must I have sipped? must you have sipped? must she have sipped? must we have sipped? must you have sipped? must they have sipped?
V-ing perfect
must I have been sipping? must you have been sipping? must she have been sipping? must we have been sipping? must you have been sipping? must they have been sipping?
Interro-negative form
Simple form
must I not sip? must you not sip? must she not sip? must we not sip? must you not sip? must they not sip?
V-ing form
must I not be sipping? must you not be sipping? must she not be sipping? must we not be sipping? must you not be sipping? must they not be sipping?
Perfect
must I not have sipped? must you not have sipped? must she not have sipped? must we not have sipped? must you not have sipped? must they not have sipped?
V-ing perfect
must I not have been sipping? must you not have been sipping? must she not have been sipping? must we not have been sipping? must you not have been sipping? must they not have been sipping?