could complain
Regular verb: complain - complained- complained

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could complain
you could complain
he could complain
we could complain
you could complain
they could complain 	I could be complaining
you could be complaining
he could be complaining
we could be complaining
you could be complaining
they could be complaining	I could have complained
you could have complained
he could have complained
we could have complained
you could have complained
they could have complained	I could have been complaining
you could have been complaining
he could have been complaining
we could have been complaining
you could have been complaining
they could have been complaining	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't complain
you couldn't complain
he couldn't complain
we couldn't complain
you couldn't complain
they couldn't complain 	I couldn't be complaining
you couldn't be complaining
he couldn't be complaining
we couldn't be complaining
you couldn't be complaining
they couldn't be complaining	I couldn't have complained
you couldn't have complained
he couldn't have complained
we couldn't have complained
you couldn't have complained
they couldn't have complained	I couldn't have been complaining
you couldn't have been complaining
he couldn't have been complaining
we couldn't have been complaining
you couldn't have been complaining
they couldn't have been complaining	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I complain?
could you complain?
could he complain?
could we complain?
could you complain?
could they complain? 	could I be complaining?
could you be complaining?
could he be complaining?
could we be complaining?
could you be complaining?
could they be complaining? 	could I have complained?
could you have complained?
could he have complained?
could we have complained?
could you have complained?
could they have complained? 	could I have been complaining?
could you have been complaining?
could he have been complaining?
could we have been complaining?
could you have been complaining?
could they have been complaining? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I complain?
couldn't you complain?
couldn't he complain?
couldn't we complain?
couldn't you complain?
couldn't they complain? 	couldn't I be complaining?
couldn't you be complaining?
couldn't he be complaining?
couldn't we be complaining?
couldn't you be complaining?
couldn't they be complaining? 	couldn't I have complained?
couldn't you have complained?
couldn't he have complained?
couldn't we have complained?
couldn't you have complained?
couldn't they have complained? 	couldn't I have been complaining?
couldn't you have been complaining?
couldn't he have been complaining?
couldn't we have been complaining?
couldn't you have been complaining?
couldn't they have been complaining?