English verb conjugation
MUST TARIFF

Regular verb: tariff - tariffed - tariffed

Affirmation

Simple form	V-ing form
I must tariff you must tariff he must tariff we must tariff you must tariff they must tariff	I must be tariffing you must be tariffing he must be tariffing we must be tariffing you must be tariffing they must be tariffing
Perfect	V-ing perfect
I must have tariffed you must have tariffed he must have tariffed we must have tariffed you must have tariffed they must have tariffed	I must have been tariffing you must have been tariffing he must have been tariffing we must have been tariffing you must have been tariffing they must have been tariffing

Negation

Simple form	V-ing form
I must not tariff you must not tariff he must not tariff we must not tariff you must not tariff they must not tariff	I must not be tariffing you must not be tariffing he must not be tariffing we must not be tariffing you must not be tariffing they must not be tariffing
Perfect	V-ing perfect
I must not have tariffed you must not have tariffed he must not have tariffed we must not have tariffed you must not have tariffed they must not have tariffed	I must not have been tariffing you must not have been tariffing he must not have been tariffing we must not have been tariffing you must not have been tariffing they must not have been tariffing

Interrogative form

Simple form	V-ing form
must I tariff? must you tariff? must he tariff? must we tariff? must you tariff? must they tariff?	must I be tariffing? must you be tariffing? must he be tariffing? must we be tariffing? must you be tariffing? must they be tariffing?
Perfect	V-ing perfect
must I have tariffed? must you have tariffed? must he have tariffed? must we have tariffed? must you have tariffed? must they have tariffed?	must I have been tariffing? must you have been tariffing? must he have been tariffing? must we have been tariffing? must you have been tariffing? must they have been tariffing?

Interro-negative form

Simple form	V-ing form
must I not tariff? must you not tariff? must he not tariff? must we not tariff? must you not tariff? must they not tariff?	must I not be tariffing? must you not be tariffing? must he not be tariffing? must we not be tariffing? must you not be tariffing? must they not be tariffing?
Perfect	V-ing perfect
must I not have tariffed? must you not have tariffed? must he not have tariffed? must we not have tariffed? must you not have tariffed? must they not have tariffed?	must I not have been tariffing? must you not have been tariffing? must he not have been tariffing? must we not have been tariffing? must you not have been tariffing? must they not have been tariffing?