could do
Irregular verb: do - did- done

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could do
you could do
he could do
we could do
you could do
they could do 	I could be doing
you could be doing
he could be doing
we could be doing
you could be doing
they could be doing	I could have done
you could have done
he could have done
we could have done
you could have done
they could have done	I could have been doing
you could have been doing
he could have been doing
we could have been doing
you could have been doing
they could have been doing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not do
you could not do
he could not do
we could not do
you could not do
they could not do 	I could not be doing
you could not be doing
he could not be doing
we could not be doing
you could not be doing
they could not be doing	I could not have done
you could not have done
he could not have done
we could not have done
you could not have done
they could not have done	I could not have been doing
you could not have been doing
he could not have been doing
we could not have been doing
you could not have been doing
they could not have been doing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I do?
could you do?
could he do?
could we do?
could you do?
could they do? 	could I be doing?
could you be doing?
could he be doing?
could we be doing?
could you be doing?
could they be doing? 	could I have done?
could you have done?
could he have done?
could we have done?
could you have done?
could they have done? 	could I have been doing?
could you have been doing?
could he have been doing?
could we have been doing?
could you have been doing?
could they have been doing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not do?
could you not do?
could he not do?
could we not do?
could you not do?
could they not do? 	could I not be doing?
could you not be doing?
could he not be doing?
could we not be doing?
could you not be doing?
could they not be doing? 	could I not have done?
could you not have done?
could he not have done?
could we not have done?
could you not have done?
could they not have done? 	could I not have been doing?
could you not have been doing?
could he not have been doing?
could we not have been doing?
could you not have been doing?
could they not have been doing?