English verb conjugation
MUST WINDSURF

Regular verb: windsurf - windsurfed - windsurfed

Affirmation

Simple form	V-ing form
I must windsurf you must windsurf she must windsurf we must windsurf you must windsurf they must windsurf	I must be windsurfing you must be windsurfing she must be windsurfing we must be windsurfing you must be windsurfing they must be windsurfing
Perfect	V-ing perfect
I must have windsurfed you must have windsurfed she must have windsurfed we must have windsurfed you must have windsurfed they must have windsurfed	I must have been windsurfing you must have been windsurfing she must have been windsurfing we must have been windsurfing you must have been windsurfing they must have been windsurfing

Negation

Simple form	V-ing form
I mustn't windsurf you mustn't windsurf she mustn't windsurf we mustn't windsurf you mustn't windsurf they mustn't windsurf	I mustn't be windsurfing you mustn't be windsurfing she mustn't be windsurfing we mustn't be windsurfing you mustn't be windsurfing they mustn't be windsurfing
Perfect	V-ing perfect
I mustn't have windsurfed you mustn't have windsurfed she mustn't have windsurfed we mustn't have windsurfed you mustn't have windsurfed they mustn't have windsurfed	I mustn't have been windsurfing you mustn't have been windsurfing she mustn't have been windsurfing we mustn't have been windsurfing you mustn't have been windsurfing they mustn't have been windsurfing

Interrogative form

Simple form	V-ing form
must I windsurf? must you windsurf? must she windsurf? must we windsurf? must you windsurf? must they windsurf?	must I be windsurfing? must you be windsurfing? must she be windsurfing? must we be windsurfing? must you be windsurfing? must they be windsurfing?
Perfect	V-ing perfect
must I have windsurfed? must you have windsurfed? must she have windsurfed? must we have windsurfed? must you have windsurfed? must they have windsurfed?	must I have been windsurfing? must you have been windsurfing? must she have been windsurfing? must we have been windsurfing? must you have been windsurfing? must they have been windsurfing?

Interro-negative form

Simple form	V-ing form
mustn't I windsurf? mustn't you windsurf? mustn't she windsurf? mustn't we windsurf? mustn't you windsurf? mustn't they windsurf?	mustn't I be windsurfing? mustn't you be windsurfing? mustn't she be windsurfing? mustn't we be windsurfing? mustn't you be windsurfing? mustn't they be windsurfing?
Perfect	V-ing perfect
mustn't I have windsurfed? mustn't you have windsurfed? mustn't she have windsurfed? mustn't we have windsurfed? mustn't you have windsurfed? mustn't they have windsurfed?	mustn't I have been windsurfing? mustn't you have been windsurfing? mustn't she have been windsurfing? mustn't we have been windsurfing? mustn't you have been windsurfing? mustn't they have been windsurfing?