could serrate
Regular verb: serrate - serrated- serrated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could serrate
you could serrate
he could serrate
we could serrate
you could serrate
they could serrate 	I could be serrating
you could be serrating
he could be serrating
we could be serrating
you could be serrating
they could be serrating	I could have serrated
you could have serrated
he could have serrated
we could have serrated
you could have serrated
they could have serrated	I could have been serrating
you could have been serrating
he could have been serrating
we could have been serrating
you could have been serrating
they could have been serrating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't serrate
you couldn't serrate
he couldn't serrate
we couldn't serrate
you couldn't serrate
they couldn't serrate 	I couldn't be serrating
you couldn't be serrating
he couldn't be serrating
we couldn't be serrating
you couldn't be serrating
they couldn't be serrating	I couldn't have serrated
you couldn't have serrated
he couldn't have serrated
we couldn't have serrated
you couldn't have serrated
they couldn't have serrated	I couldn't have been serrating
you couldn't have been serrating
he couldn't have been serrating
we couldn't have been serrating
you couldn't have been serrating
they couldn't have been serrating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I serrate?
could you serrate?
could he serrate?
could we serrate?
could you serrate?
could they serrate? 	could I be serrating?
could you be serrating?
could he be serrating?
could we be serrating?
could you be serrating?
could they be serrating? 	could I have serrated?
could you have serrated?
could he have serrated?
could we have serrated?
could you have serrated?
could they have serrated? 	could I have been serrating?
could you have been serrating?
could he have been serrating?
could we have been serrating?
could you have been serrating?
could they have been serrating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I serrate?
couldn't you serrate?
couldn't he serrate?
couldn't we serrate?
couldn't you serrate?
couldn't they serrate? 	couldn't I be serrating?
couldn't you be serrating?
couldn't he be serrating?
couldn't we be serrating?
couldn't you be serrating?
couldn't they be serrating? 	couldn't I have serrated?
couldn't you have serrated?
couldn't he have serrated?
couldn't we have serrated?
couldn't you have serrated?
couldn't they have serrated? 	couldn't I have been serrating?
couldn't you have been serrating?
couldn't he have been serrating?
couldn't we have been serrating?
couldn't you have been serrating?
couldn't they have been serrating?