I must couple you must couple he must couple we must couple you must couple they must couple
V-ing form
I must be coupling you must be coupling he must be coupling we must be coupling you must be coupling they must be coupling
Perfect
I must have coupled you must have coupled he must have coupled we must have coupled you must have coupled they must have coupled
V-ing perfect
I must have been coupling you must have been coupling he must have been coupling we must have been coupling you must have been coupling they must have been coupling
Negation
Simple form
I must not couple you must not couple he must not couple we must not couple you must not couple they must not couple
V-ing form
I must not be coupling you must not be coupling he must not be coupling we must not be coupling you must not be coupling they must not be coupling
Perfect
I must not have coupled you must not have coupled he must not have coupled we must not have coupled you must not have coupled they must not have coupled
V-ing perfect
I must not have been coupling you must not have been coupling he must not have been coupling we must not have been coupling you must not have been coupling they must not have been coupling
Interrogative form
Simple form
must I couple? must you couple? must he couple? must we couple? must you couple? must they couple?
V-ing form
must I be coupling? must you be coupling? must he be coupling? must we be coupling? must you be coupling? must they be coupling?
Perfect
must I have coupled? must you have coupled? must he have coupled? must we have coupled? must you have coupled? must they have coupled?
V-ing perfect
must I have been coupling? must you have been coupling? must he have been coupling? must we have been coupling? must you have been coupling? must they have been coupling?
Interro-negative form
Simple form
must I not couple? must you not couple? must he not couple? must we not couple? must you not couple? must they not couple?
V-ing form
must I not be coupling? must you not be coupling? must he not be coupling? must we not be coupling? must you not be coupling? must they not be coupling?
Perfect
must I not have coupled? must you not have coupled? must he not have coupled? must we not have coupled? must you not have coupled? must they not have coupled?
V-ing perfect
must I not have been coupling? must you not have been coupling? must he not have been coupling? must we not have been coupling? must you not have been coupling? must they not have been coupling?