could assist
Regular verb: assist - assisted- assisted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could assist
you could assist
he could assist
we could assist
you could assist
they could assist 	I could be assisting
you could be assisting
he could be assisting
we could be assisting
you could be assisting
they could be assisting	I could have assisted
you could have assisted
he could have assisted
we could have assisted
you could have assisted
they could have assisted	I could have been assisting
you could have been assisting
he could have been assisting
we could have been assisting
you could have been assisting
they could have been assisting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't assist
you couldn't assist
he couldn't assist
we couldn't assist
you couldn't assist
they couldn't assist 	I couldn't be assisting
you couldn't be assisting
he couldn't be assisting
we couldn't be assisting
you couldn't be assisting
they couldn't be assisting	I couldn't have assisted
you couldn't have assisted
he couldn't have assisted
we couldn't have assisted
you couldn't have assisted
they couldn't have assisted	I couldn't have been assisting
you couldn't have been assisting
he couldn't have been assisting
we couldn't have been assisting
you couldn't have been assisting
they couldn't have been assisting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I assist?
could you assist?
could he assist?
could we assist?
could you assist?
could they assist? 	could I be assisting?
could you be assisting?
could he be assisting?
could we be assisting?
could you be assisting?
could they be assisting? 	could I have assisted?
could you have assisted?
could he have assisted?
could we have assisted?
could you have assisted?
could they have assisted? 	could I have been assisting?
could you have been assisting?
could he have been assisting?
could we have been assisting?
could you have been assisting?
could they have been assisting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I assist?
couldn't you assist?
couldn't he assist?
couldn't we assist?
couldn't you assist?
couldn't they assist? 	couldn't I be assisting?
couldn't you be assisting?
couldn't he be assisting?
couldn't we be assisting?
couldn't you be assisting?
couldn't they be assisting? 	couldn't I have assisted?
couldn't you have assisted?
couldn't he have assisted?
couldn't we have assisted?
couldn't you have assisted?
couldn't they have assisted? 	couldn't I have been assisting?
couldn't you have been assisting?
couldn't he have been assisting?
couldn't we have been assisting?
couldn't you have been assisting?
couldn't they have been assisting?