English verb conjugation
MUST CROSSRUFF

Regular verb: crossruff - crossruffed - crossruffed

Affirmation

Simple form	V-ing form
I must crossruff you must crossruff he must crossruff we must crossruff you must crossruff they must crossruff	I must be crossruffing you must be crossruffing he must be crossruffing we must be crossruffing you must be crossruffing they must be crossruffing
Perfect	V-ing perfect
I must have crossruffed you must have crossruffed he must have crossruffed we must have crossruffed you must have crossruffed they must have crossruffed	I must have been crossruffing you must have been crossruffing he must have been crossruffing we must have been crossruffing you must have been crossruffing they must have been crossruffing

Negation

Simple form	V-ing form
I mustn't crossruff you mustn't crossruff he mustn't crossruff we mustn't crossruff you mustn't crossruff they mustn't crossruff	I mustn't be crossruffing you mustn't be crossruffing he mustn't be crossruffing we mustn't be crossruffing you mustn't be crossruffing they mustn't be crossruffing
Perfect	V-ing perfect
I mustn't have crossruffed you mustn't have crossruffed he mustn't have crossruffed we mustn't have crossruffed you mustn't have crossruffed they mustn't have crossruffed	I mustn't have been crossruffing you mustn't have been crossruffing he mustn't have been crossruffing we mustn't have been crossruffing you mustn't have been crossruffing they mustn't have been crossruffing

Interrogative form

Simple form	V-ing form
must I crossruff? must you crossruff? must he crossruff? must we crossruff? must you crossruff? must they crossruff?	must I be crossruffing? must you be crossruffing? must he be crossruffing? must we be crossruffing? must you be crossruffing? must they be crossruffing?
Perfect	V-ing perfect
must I have crossruffed? must you have crossruffed? must he have crossruffed? must we have crossruffed? must you have crossruffed? must they have crossruffed?	must I have been crossruffing? must you have been crossruffing? must he have been crossruffing? must we have been crossruffing? must you have been crossruffing? must they have been crossruffing?

Interro-negative form

Simple form	V-ing form
mustn't I crossruff? mustn't you crossruff? mustn't he crossruff? mustn't we crossruff? mustn't you crossruff? mustn't they crossruff?	mustn't I be crossruffing? mustn't you be crossruffing? mustn't he be crossruffing? mustn't we be crossruffing? mustn't you be crossruffing? mustn't they be crossruffing?
Perfect	V-ing perfect
mustn't I have crossruffed? mustn't you have crossruffed? mustn't he have crossruffed? mustn't we have crossruffed? mustn't you have crossruffed? mustn't they have crossruffed?	mustn't I have been crossruffing? mustn't you have been crossruffing? mustn't he have been crossruffing? mustn't we have been crossruffing? mustn't you have been crossruffing? mustn't they have been crossruffing?