must crouch
Regular verb: crouch - crouched- crouched

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must crouch
you must crouch
she must crouch
we must crouch
you must crouch
they must crouch 	I must be crouching
you must be crouching
she must be crouching
we must be crouching
you must be crouching
they must be crouching	I must have crouched
you must have crouched
she must have crouched
we must have crouched
you must have crouched
they must have crouched	I must have been crouching
you must have been crouching
she must have been crouching
we must have been crouching
you must have been crouching
they must have been crouching	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't crouch
you mustn't crouch
she mustn't crouch
we mustn't crouch
you mustn't crouch
they mustn't crouch 	I mustn't be crouching
you mustn't be crouching
she mustn't be crouching
we mustn't be crouching
you mustn't be crouching
they mustn't be crouching	I mustn't have crouched
you mustn't have crouched
she mustn't have crouched
we mustn't have crouched
you mustn't have crouched
they mustn't have crouched	I mustn't have been crouching
you mustn't have been crouching
she mustn't have been crouching
we mustn't have been crouching
you mustn't have been crouching
they mustn't have been crouching	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I crouch?
must you crouch?
must she crouch?
must we crouch?
must you crouch?
must they crouch? 	must I be crouching?
must you be crouching?
must she be crouching?
must we be crouching?
must you be crouching?
must they be crouching? 	must I have crouched?
must you have crouched?
must she have crouched?
must we have crouched?
must you have crouched?
must they have crouched? 	must I have been crouching?
must you have been crouching?
must she have been crouching?
must we have been crouching?
must you have been crouching?
must they have been crouching? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I crouch?
mustn't you crouch?
mustn't she crouch?
mustn't we crouch?
mustn't you crouch?
mustn't they crouch? 	mustn't I be crouching?
mustn't you be crouching?
mustn't she be crouching?
mustn't we be crouching?
mustn't you be crouching?
mustn't they be crouching? 	mustn't I have crouched?
mustn't you have crouched?
mustn't she have crouched?
mustn't we have crouched?
mustn't you have crouched?
mustn't they have crouched? 	mustn't I have been crouching?
mustn't you have been crouching?
mustn't she have been crouching?
mustn't we have been crouching?
mustn't you have been crouching?
mustn't they have been crouching?