English verb conjugation
MUST HEADBUTT

Regular verb: headbutt - headbutted - headbutted

Affirmation

Simple form	V-ing form
I must headbutt you must headbutt he must headbutt we must headbutt you must headbutt they must headbutt	I must be headbutting you must be headbutting he must be headbutting we must be headbutting you must be headbutting they must be headbutting
Perfect	V-ing perfect
I must have headbutted you must have headbutted he must have headbutted we must have headbutted you must have headbutted they must have headbutted	I must have been headbutting you must have been headbutting he must have been headbutting we must have been headbutting you must have been headbutting they must have been headbutting

Negation

Simple form	V-ing form
I mustn't headbutt you mustn't headbutt he mustn't headbutt we mustn't headbutt you mustn't headbutt they mustn't headbutt	I mustn't be headbutting you mustn't be headbutting he mustn't be headbutting we mustn't be headbutting you mustn't be headbutting they mustn't be headbutting
Perfect	V-ing perfect
I mustn't have headbutted you mustn't have headbutted he mustn't have headbutted we mustn't have headbutted you mustn't have headbutted they mustn't have headbutted	I mustn't have been headbutting you mustn't have been headbutting he mustn't have been headbutting we mustn't have been headbutting you mustn't have been headbutting they mustn't have been headbutting

Interrogative form

Simple form	V-ing form
must I headbutt? must you headbutt? must he headbutt? must we headbutt? must you headbutt? must they headbutt?	must I be headbutting? must you be headbutting? must he be headbutting? must we be headbutting? must you be headbutting? must they be headbutting?
Perfect	V-ing perfect
must I have headbutted? must you have headbutted? must he have headbutted? must we have headbutted? must you have headbutted? must they have headbutted?	must I have been headbutting? must you have been headbutting? must he have been headbutting? must we have been headbutting? must you have been headbutting? must they have been headbutting?

Interro-negative form

Simple form	V-ing form
mustn't I headbutt? mustn't you headbutt? mustn't he headbutt? mustn't we headbutt? mustn't you headbutt? mustn't they headbutt?	mustn't I be headbutting? mustn't you be headbutting? mustn't he be headbutting? mustn't we be headbutting? mustn't you be headbutting? mustn't they be headbutting?
Perfect	V-ing perfect
mustn't I have headbutted? mustn't you have headbutted? mustn't he have headbutted? mustn't we have headbutted? mustn't you have headbutted? mustn't they have headbutted?	mustn't I have been headbutting? mustn't you have been headbutting? mustn't he have been headbutting? mustn't we have been headbutting? mustn't you have been headbutting? mustn't they have been headbutting?