can demonstrate
Regular verb: demonstrate - demonstrated- demonstrated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can demonstrate
you can demonstrate
he can demonstrate
we can demonstrate
you can demonstrate
they can demonstrate 	I can be demonstrating
you can be demonstrating
he can be demonstrating
we can be demonstrating
you can be demonstrating
they can be demonstrating	I can have demonstrated
you can have demonstrated
he can have demonstrated
we can have demonstrated
you can have demonstrated
they can have demonstrated	I can have been demonstrating
you can have been demonstrating
he can have been demonstrating
we can have been demonstrating
you can have been demonstrating
they can have been demonstrating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't demonstrate
you can't demonstrate
he can't demonstrate
we can't demonstrate
you can't demonstrate
they can't demonstrate 	I can't be demonstrating
you can't be demonstrating
he can't be demonstrating
we can't be demonstrating
you can't be demonstrating
they can't be demonstrating	I can't have demonstrated
you can't have demonstrated
he can't have demonstrated
we can't have demonstrated
you can't have demonstrated
they can't have demonstrated	I can't have been demonstrating
you can't have been demonstrating
he can't have been demonstrating
we can't have been demonstrating
you can't have been demonstrating
they can't have been demonstrating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I demonstrate?
can you demonstrate?
can he demonstrate?
can we demonstrate?
can you demonstrate?
can they demonstrate? 	can I be demonstrating?
can you be demonstrating?
can he be demonstrating?
can we be demonstrating?
can you be demonstrating?
can they be demonstrating? 	can I have demonstrated?
can you have demonstrated?
can he have demonstrated?
can we have demonstrated?
can you have demonstrated?
can they have demonstrated? 	can I have been demonstrating?
can you have been demonstrating?
can he have been demonstrating?
can we have been demonstrating?
can you have been demonstrating?
can they have been demonstrating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I demonstrate?
can't you demonstrate?
can't he demonstrate?
can't we demonstrate?
can't you demonstrate?
can't they demonstrate? 	can't I be demonstrating?
can't you be demonstrating?
can't he be demonstrating?
can't we be demonstrating?
can't you be demonstrating?
can't they be demonstrating? 	can't I have demonstrated?
can't you have demonstrated?
can't he have demonstrated?
can't we have demonstrated?
can't you have demonstrated?
can't they have demonstrated? 	can't I have been demonstrating?
can't you have been demonstrating?
can't he have been demonstrating?
can't we have been demonstrating?
can't you have been demonstrating?
can't they have been demonstrating?