can lighten
Regular verb: lighten - lightened- lightened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can lighten
you can lighten
she can lighten
we can lighten
you can lighten
they can lighten 	I can be lightening
you can be lightening
she can be lightening
we can be lightening
you can be lightening
they can be lightening	I can have lightened
you can have lightened
she can have lightened
we can have lightened
you can have lightened
they can have lightened	I can have been lightening
you can have been lightening
she can have been lightening
we can have been lightening
you can have been lightening
they can have been lightening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can't lighten
you can't lighten
she can't lighten
we can't lighten
you can't lighten
they can't lighten 	I can't be lightening
you can't be lightening
she can't be lightening
we can't be lightening
you can't be lightening
they can't be lightening	I can't have lightened
you can't have lightened
she can't have lightened
we can't have lightened
you can't have lightened
they can't have lightened	I can't have been lightening
you can't have been lightening
she can't have been lightening
we can't have been lightening
you can't have been lightening
they can't have been lightening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I lighten?
can you lighten?
can she lighten?
can we lighten?
can you lighten?
can they lighten? 	can I be lightening?
can you be lightening?
can she be lightening?
can we be lightening?
can you be lightening?
can they be lightening? 	can I have lightened?
can you have lightened?
can she have lightened?
can we have lightened?
can you have lightened?
can they have lightened? 	can I have been lightening?
can you have been lightening?
can she have been lightening?
can we have been lightening?
can you have been lightening?
can they have been lightening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can't I lighten?
can't you lighten?
can't she lighten?
can't we lighten?
can't you lighten?
can't they lighten? 	can't I be lightening?
can't you be lightening?
can't she be lightening?
can't we be lightening?
can't you be lightening?
can't they be lightening? 	can't I have lightened?
can't you have lightened?
can't she have lightened?
can't we have lightened?
can't you have lightened?
can't they have lightened? 	can't I have been lightening?
can't you have been lightening?
can't she have been lightening?
can't we have been lightening?
can't you have been lightening?
can't they have been lightening?