could abstract
Regular verb: abstract - abstracted- abstracted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could abstract
you could abstract
she could abstract
we could abstract
you could abstract
they could abstract 	I could be abstracting
you could be abstracting
she could be abstracting
we could be abstracting
you could be abstracting
they could be abstracting	I could have abstracted
you could have abstracted
she could have abstracted
we could have abstracted
you could have abstracted
they could have abstracted	I could have been abstracting
you could have been abstracting
she could have been abstracting
we could have been abstracting
you could have been abstracting
they could have been abstracting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't abstract
you couldn't abstract
she couldn't abstract
we couldn't abstract
you couldn't abstract
they couldn't abstract 	I couldn't be abstracting
you couldn't be abstracting
she couldn't be abstracting
we couldn't be abstracting
you couldn't be abstracting
they couldn't be abstracting	I couldn't have abstracted
you couldn't have abstracted
she couldn't have abstracted
we couldn't have abstracted
you couldn't have abstracted
they couldn't have abstracted	I couldn't have been abstracting
you couldn't have been abstracting
she couldn't have been abstracting
we couldn't have been abstracting
you couldn't have been abstracting
they couldn't have been abstracting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I abstract?
could you abstract?
could she abstract?
could we abstract?
could you abstract?
could they abstract? 	could I be abstracting?
could you be abstracting?
could she be abstracting?
could we be abstracting?
could you be abstracting?
could they be abstracting? 	could I have abstracted?
could you have abstracted?
could she have abstracted?
could we have abstracted?
could you have abstracted?
could they have abstracted? 	could I have been abstracting?
could you have been abstracting?
could she have been abstracting?
could we have been abstracting?
could you have been abstracting?
could they have been abstracting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I abstract?
couldn't you abstract?
couldn't she abstract?
couldn't we abstract?
couldn't you abstract?
couldn't they abstract? 	couldn't I be abstracting?
couldn't you be abstracting?
couldn't she be abstracting?
couldn't we be abstracting?
couldn't you be abstracting?
couldn't they be abstracting? 	couldn't I have abstracted?
couldn't you have abstracted?
couldn't she have abstracted?
couldn't we have abstracted?
couldn't you have abstracted?
couldn't they have abstracted? 	couldn't I have been abstracting?
couldn't you have been abstracting?
couldn't she have been abstracting?
couldn't we have been abstracting?
couldn't you have been abstracting?
couldn't they have been abstracting?