could sputter
Regular verb: sputter - sputtered- sputtered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could sputter
you could sputter
she could sputter
we could sputter
you could sputter
they could sputter 	I could be sputtering
you could be sputtering
she could be sputtering
we could be sputtering
you could be sputtering
they could be sputtering	I could have sputtered
you could have sputtered
she could have sputtered
we could have sputtered
you could have sputtered
they could have sputtered	I could have been sputtering
you could have been sputtering
she could have been sputtering
we could have been sputtering
you could have been sputtering
they could have been sputtering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't sputter
you couldn't sputter
she couldn't sputter
we couldn't sputter
you couldn't sputter
they couldn't sputter 	I couldn't be sputtering
you couldn't be sputtering
she couldn't be sputtering
we couldn't be sputtering
you couldn't be sputtering
they couldn't be sputtering	I couldn't have sputtered
you couldn't have sputtered
she couldn't have sputtered
we couldn't have sputtered
you couldn't have sputtered
they couldn't have sputtered	I couldn't have been sputtering
you couldn't have been sputtering
she couldn't have been sputtering
we couldn't have been sputtering
you couldn't have been sputtering
they couldn't have been sputtering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I sputter?
could you sputter?
could she sputter?
could we sputter?
could you sputter?
could they sputter? 	could I be sputtering?
could you be sputtering?
could she be sputtering?
could we be sputtering?
could you be sputtering?
could they be sputtering? 	could I have sputtered?
could you have sputtered?
could she have sputtered?
could we have sputtered?
could you have sputtered?
could they have sputtered? 	could I have been sputtering?
could you have been sputtering?
could she have been sputtering?
could we have been sputtering?
could you have been sputtering?
could they have been sputtering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I sputter?
couldn't you sputter?
couldn't she sputter?
couldn't we sputter?
couldn't you sputter?
couldn't they sputter? 	couldn't I be sputtering?
couldn't you be sputtering?
couldn't she be sputtering?
couldn't we be sputtering?
couldn't you be sputtering?
couldn't they be sputtering? 	couldn't I have sputtered?
couldn't you have sputtered?
couldn't she have sputtered?
couldn't we have sputtered?
couldn't you have sputtered?
couldn't they have sputtered? 	couldn't I have been sputtering?
couldn't you have been sputtering?
couldn't she have been sputtering?
couldn't we have been sputtering?
couldn't you have been sputtering?
couldn't they have been sputtering?