could congratulate
Regular verb: congratulate - congratulated- congratulated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could congratulate
you could congratulate
she could congratulate
we could congratulate
you could congratulate
they could congratulate 	I could be congratulating
you could be congratulating
she could be congratulating
we could be congratulating
you could be congratulating
they could be congratulating	I could have congratulated
you could have congratulated
she could have congratulated
we could have congratulated
you could have congratulated
they could have congratulated	I could have been congratulating
you could have been congratulating
she could have been congratulating
we could have been congratulating
you could have been congratulating
they could have been congratulating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't congratulate
you couldn't congratulate
she couldn't congratulate
we couldn't congratulate
you couldn't congratulate
they couldn't congratulate 	I couldn't be congratulating
you couldn't be congratulating
she couldn't be congratulating
we couldn't be congratulating
you couldn't be congratulating
they couldn't be congratulating	I couldn't have congratulated
you couldn't have congratulated
she couldn't have congratulated
we couldn't have congratulated
you couldn't have congratulated
they couldn't have congratulated	I couldn't have been congratulating
you couldn't have been congratulating
she couldn't have been congratulating
we couldn't have been congratulating
you couldn't have been congratulating
they couldn't have been congratulating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I congratulate?
could you congratulate?
could she congratulate?
could we congratulate?
could you congratulate?
could they congratulate? 	could I be congratulating?
could you be congratulating?
could she be congratulating?
could we be congratulating?
could you be congratulating?
could they be congratulating? 	could I have congratulated?
could you have congratulated?
could she have congratulated?
could we have congratulated?
could you have congratulated?
could they have congratulated? 	could I have been congratulating?
could you have been congratulating?
could she have been congratulating?
could we have been congratulating?
could you have been congratulating?
could they have been congratulating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I congratulate?
couldn't you congratulate?
couldn't she congratulate?
couldn't we congratulate?
couldn't you congratulate?
couldn't they congratulate? 	couldn't I be congratulating?
couldn't you be congratulating?
couldn't she be congratulating?
couldn't we be congratulating?
couldn't you be congratulating?
couldn't they be congratulating? 	couldn't I have congratulated?
couldn't you have congratulated?
couldn't she have congratulated?
couldn't we have congratulated?
couldn't you have congratulated?
couldn't they have congratulated? 	couldn't I have been congratulating?
couldn't you have been congratulating?
couldn't she have been congratulating?
couldn't we have been congratulating?
couldn't you have been congratulating?
couldn't they have been congratulating?