can heighten
Regular verb: heighten - heightened- heightened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can heighten
you can heighten
she can heighten
we can heighten
you can heighten
they can heighten 	I can be heightening
you can be heightening
she can be heightening
we can be heightening
you can be heightening
they can be heightening	I can have heightened
you can have heightened
she can have heightened
we can have heightened
you can have heightened
they can have heightened	I can have been heightening
you can have been heightening
she can have been heightening
we can have been heightening
you can have been heightening
they can have been heightening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't heighten
you can't heighten
she can't heighten
we can't heighten
you can't heighten
they can't heighten 	I can't be heightening
you can't be heightening
she can't be heightening
we can't be heightening
you can't be heightening
they can't be heightening	I can't have heightened
you can't have heightened
she can't have heightened
we can't have heightened
you can't have heightened
they can't have heightened	I can't have been heightening
you can't have been heightening
she can't have been heightening
we can't have been heightening
you can't have been heightening
they can't have been heightening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I heighten?
can you heighten?
can she heighten?
can we heighten?
can you heighten?
can they heighten? 	can I be heightening?
can you be heightening?
can she be heightening?
can we be heightening?
can you be heightening?
can they be heightening? 	can I have heightened?
can you have heightened?
can she have heightened?
can we have heightened?
can you have heightened?
can they have heightened? 	can I have been heightening?
can you have been heightening?
can she have been heightening?
can we have been heightening?
can you have been heightening?
can they have been heightening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I heighten?
can't you heighten?
can't she heighten?
can't we heighten?
can't you heighten?
can't they heighten? 	can't I be heightening?
can't you be heightening?
can't she be heightening?
can't we be heightening?
can't you be heightening?
can't they be heightening? 	can't I have heightened?
can't you have heightened?
can't she have heightened?
can't we have heightened?
can't you have heightened?
can't they have heightened? 	can't I have been heightening?
can't you have been heightening?
can't she have been heightening?
can't we have been heightening?
can't you have been heightening?
can't they have been heightening?