could referee
Regular verb: referee - refereed- refereed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could referee
you could referee
he could referee
we could referee
you could referee
they could referee 	I could be refereeing
you could be refereeing
he could be refereeing
we could be refereeing
you could be refereeing
they could be refereeing	I could have refereed
you could have refereed
he could have refereed
we could have refereed
you could have refereed
they could have refereed	I could have been refereeing
you could have been refereeing
he could have been refereeing
we could have been refereeing
you could have been refereeing
they could have been refereeing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not referee
you could not referee
he could not referee
we could not referee
you could not referee
they could not referee 	I could not be refereeing
you could not be refereeing
he could not be refereeing
we could not be refereeing
you could not be refereeing
they could not be refereeing	I could not have refereed
you could not have refereed
he could not have refereed
we could not have refereed
you could not have refereed
they could not have refereed	I could not have been refereeing
you could not have been refereeing
he could not have been refereeing
we could not have been refereeing
you could not have been refereeing
they could not have been refereeing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I referee?
could you referee?
could he referee?
could we referee?
could you referee?
could they referee? 	could I be refereeing?
could you be refereeing?
could he be refereeing?
could we be refereeing?
could you be refereeing?
could they be refereeing? 	could I have refereed?
could you have refereed?
could he have refereed?
could we have refereed?
could you have refereed?
could they have refereed? 	could I have been refereeing?
could you have been refereeing?
could he have been refereeing?
could we have been refereeing?
could you have been refereeing?
could they have been refereeing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not referee?
could you not referee?
could he not referee?
could we not referee?
could you not referee?
could they not referee? 	could I not be refereeing?
could you not be refereeing?
could he not be refereeing?
could we not be refereeing?
could you not be refereeing?
could they not be refereeing? 	could I not have refereed?
could you not have refereed?
could he not have refereed?
could we not have refereed?
could you not have refereed?
could they not have refereed? 	could I not have been refereeing?
could you not have been refereeing?
could he not have been refereeing?
could we not have been refereeing?
could you not have been refereeing?
could they not have been refereeing?