could protrude
Regular verb: protrude - protruded- protruded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could protrude
you could protrude
she could protrude
we could protrude
you could protrude
they could protrude 	I could be protruding
you could be protruding
she could be protruding
we could be protruding
you could be protruding
they could be protruding	I could have protruded
you could have protruded
she could have protruded
we could have protruded
you could have protruded
they could have protruded	I could have been protruding
you could have been protruding
she could have been protruding
we could have been protruding
you could have been protruding
they could have been protruding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't protrude
you couldn't protrude
she couldn't protrude
we couldn't protrude
you couldn't protrude
they couldn't protrude 	I couldn't be protruding
you couldn't be protruding
she couldn't be protruding
we couldn't be protruding
you couldn't be protruding
they couldn't be protruding	I couldn't have protruded
you couldn't have protruded
she couldn't have protruded
we couldn't have protruded
you couldn't have protruded
they couldn't have protruded	I couldn't have been protruding
you couldn't have been protruding
she couldn't have been protruding
we couldn't have been protruding
you couldn't have been protruding
they couldn't have been protruding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I protrude?
could you protrude?
could she protrude?
could we protrude?
could you protrude?
could they protrude? 	could I be protruding?
could you be protruding?
could she be protruding?
could we be protruding?
could you be protruding?
could they be protruding? 	could I have protruded?
could you have protruded?
could she have protruded?
could we have protruded?
could you have protruded?
could they have protruded? 	could I have been protruding?
could you have been protruding?
could she have been protruding?
could we have been protruding?
could you have been protruding?
could they have been protruding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I protrude?
couldn't you protrude?
couldn't she protrude?
couldn't we protrude?
couldn't you protrude?
couldn't they protrude? 	couldn't I be protruding?
couldn't you be protruding?
couldn't she be protruding?
couldn't we be protruding?
couldn't you be protruding?
couldn't they be protruding? 	couldn't I have protruded?
couldn't you have protruded?
couldn't she have protruded?
couldn't we have protruded?
couldn't you have protruded?
couldn't they have protruded? 	couldn't I have been protruding?
couldn't you have been protruding?
couldn't she have been protruding?
couldn't we have been protruding?
couldn't you have been protruding?
couldn't they have been protruding?