could shorten
Regular verb: shorten - shortened- shortened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could shorten
you could shorten
she could shorten
we could shorten
you could shorten
they could shorten 	I could be shortening
you could be shortening
she could be shortening
we could be shortening
you could be shortening
they could be shortening	I could have shortened
you could have shortened
she could have shortened
we could have shortened
you could have shortened
they could have shortened	I could have been shortening
you could have been shortening
she could have been shortening
we could have been shortening
you could have been shortening
they could have been shortening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't shorten
you couldn't shorten
she couldn't shorten
we couldn't shorten
you couldn't shorten
they couldn't shorten 	I couldn't be shortening
you couldn't be shortening
she couldn't be shortening
we couldn't be shortening
you couldn't be shortening
they couldn't be shortening	I couldn't have shortened
you couldn't have shortened
she couldn't have shortened
we couldn't have shortened
you couldn't have shortened
they couldn't have shortened	I couldn't have been shortening
you couldn't have been shortening
she couldn't have been shortening
we couldn't have been shortening
you couldn't have been shortening
they couldn't have been shortening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I shorten?
could you shorten?
could she shorten?
could we shorten?
could you shorten?
could they shorten? 	could I be shortening?
could you be shortening?
could she be shortening?
could we be shortening?
could you be shortening?
could they be shortening? 	could I have shortened?
could you have shortened?
could she have shortened?
could we have shortened?
could you have shortened?
could they have shortened? 	could I have been shortening?
could you have been shortening?
could she have been shortening?
could we have been shortening?
could you have been shortening?
could they have been shortening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I shorten?
couldn't you shorten?
couldn't she shorten?
couldn't we shorten?
couldn't you shorten?
couldn't they shorten? 	couldn't I be shortening?
couldn't you be shortening?
couldn't she be shortening?
couldn't we be shortening?
couldn't you be shortening?
couldn't they be shortening? 	couldn't I have shortened?
couldn't you have shortened?
couldn't she have shortened?
couldn't we have shortened?
couldn't you have shortened?
couldn't they have shortened? 	couldn't I have been shortening?
couldn't you have been shortening?
couldn't she have been shortening?
couldn't we have been shortening?
couldn't you have been shortening?
couldn't they have been shortening?