could concoct
Regular verb: concoct - concocted- concocted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could concoct
you could concoct
he could concoct
we could concoct
you could concoct
they could concoct 	I could be concocting
you could be concocting
he could be concocting
we could be concocting
you could be concocting
they could be concocting	I could have concocted
you could have concocted
he could have concocted
we could have concocted
you could have concocted
they could have concocted	I could have been concocting
you could have been concocting
he could have been concocting
we could have been concocting
you could have been concocting
they could have been concocting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't concoct
you couldn't concoct
he couldn't concoct
we couldn't concoct
you couldn't concoct
they couldn't concoct 	I couldn't be concocting
you couldn't be concocting
he couldn't be concocting
we couldn't be concocting
you couldn't be concocting
they couldn't be concocting	I couldn't have concocted
you couldn't have concocted
he couldn't have concocted
we couldn't have concocted
you couldn't have concocted
they couldn't have concocted	I couldn't have been concocting
you couldn't have been concocting
he couldn't have been concocting
we couldn't have been concocting
you couldn't have been concocting
they couldn't have been concocting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I concoct?
could you concoct?
could he concoct?
could we concoct?
could you concoct?
could they concoct? 	could I be concocting?
could you be concocting?
could he be concocting?
could we be concocting?
could you be concocting?
could they be concocting? 	could I have concocted?
could you have concocted?
could he have concocted?
could we have concocted?
could you have concocted?
could they have concocted? 	could I have been concocting?
could you have been concocting?
could he have been concocting?
could we have been concocting?
could you have been concocting?
could they have been concocting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I concoct?
couldn't you concoct?
couldn't he concoct?
couldn't we concoct?
couldn't you concoct?
couldn't they concoct? 	couldn't I be concocting?
couldn't you be concocting?
couldn't he be concocting?
couldn't we be concocting?
couldn't you be concocting?
couldn't they be concocting? 	couldn't I have concocted?
couldn't you have concocted?
couldn't he have concocted?
couldn't we have concocted?
couldn't you have concocted?
couldn't they have concocted? 	couldn't I have been concocting?
couldn't you have been concocting?
couldn't he have been concocting?
couldn't we have been concocting?
couldn't you have been concocting?
couldn't they have been concocting?