could quad
Regular verb: quad - quaded- quaded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could quad
you could quad
he could quad
we could quad
you could quad
they could quad 	I could be quading
you could be quading
he could be quading
we could be quading
you could be quading
they could be quading	I could have quaded
you could have quaded
he could have quaded
we could have quaded
you could have quaded
they could have quaded	I could have been quading
you could have been quading
he could have been quading
we could have been quading
you could have been quading
they could have been quading	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not quad
you could not quad
he could not quad
we could not quad
you could not quad
they could not quad 	I could not be quading
you could not be quading
he could not be quading
we could not be quading
you could not be quading
they could not be quading	I could not have quaded
you could not have quaded
he could not have quaded
we could not have quaded
you could not have quaded
they could not have quaded	I could not have been quading
you could not have been quading
he could not have been quading
we could not have been quading
you could not have been quading
they could not have been quading	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I quad?
could you quad?
could he quad?
could we quad?
could you quad?
could they quad? 	could I be quading?
could you be quading?
could he be quading?
could we be quading?
could you be quading?
could they be quading? 	could I have quaded?
could you have quaded?
could he have quaded?
could we have quaded?
could you have quaded?
could they have quaded? 	could I have been quading?
could you have been quading?
could he have been quading?
could we have been quading?
could you have been quading?
could they have been quading? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not quad?
could you not quad?
could he not quad?
could we not quad?
could you not quad?
could they not quad? 	could I not be quading?
could you not be quading?
could he not be quading?
could we not be quading?
could you not be quading?
could they not be quading? 	could I not have quaded?
could you not have quaded?
could he not have quaded?
could we not have quaded?
could you not have quaded?
could they not have quaded? 	could I not have been quading?
could you not have been quading?
could he not have been quading?
could we not have been quading?
could you not have been quading?
could they not have been quading?