can constrain
Regular verb: constrain - constrained- constrained

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can constrain
you can constrain
he can constrain
we can constrain
you can constrain
they can constrain 	I can be constraining
you can be constraining
he can be constraining
we can be constraining
you can be constraining
they can be constraining	I can have constrained
you can have constrained
he can have constrained
we can have constrained
you can have constrained
they can have constrained	I can have been constraining
you can have been constraining
he can have been constraining
we can have been constraining
you can have been constraining
they can have been constraining	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't constrain
you can't constrain
he can't constrain
we can't constrain
you can't constrain
they can't constrain 	I can't be constraining
you can't be constraining
he can't be constraining
we can't be constraining
you can't be constraining
they can't be constraining	I can't have constrained
you can't have constrained
he can't have constrained
we can't have constrained
you can't have constrained
they can't have constrained	I can't have been constraining
you can't have been constraining
he can't have been constraining
we can't have been constraining
you can't have been constraining
they can't have been constraining	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I constrain?
can you constrain?
can he constrain?
can we constrain?
can you constrain?
can they constrain? 	can I be constraining?
can you be constraining?
can he be constraining?
can we be constraining?
can you be constraining?
can they be constraining? 	can I have constrained?
can you have constrained?
can he have constrained?
can we have constrained?
can you have constrained?
can they have constrained? 	can I have been constraining?
can you have been constraining?
can he have been constraining?
can we have been constraining?
can you have been constraining?
can they have been constraining? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I constrain?
can't you constrain?
can't he constrain?
can't we constrain?
can't you constrain?
can't they constrain? 	can't I be constraining?
can't you be constraining?
can't he be constraining?
can't we be constraining?
can't you be constraining?
can't they be constraining? 	can't I have constrained?
can't you have constrained?
can't he have constrained?
can't we have constrained?
can't you have constrained?
can't they have constrained? 	can't I have been constraining?
can't you have been constraining?
can't he have been constraining?
can't we have been constraining?
can't you have been constraining?
can't they have been constraining?