could pip
Regular verb: pip - pipped- pipped

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could pip
you could pip
he could pip
we could pip
you could pip
they could pip 	I could be pipping
you could be pipping
he could be pipping
we could be pipping
you could be pipping
they could be pipping	I could have pipped
you could have pipped
he could have pipped
we could have pipped
you could have pipped
they could have pipped	I could have been pipping
you could have been pipping
he could have been pipping
we could have been pipping
you could have been pipping
they could have been pipping	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't pip
you couldn't pip
he couldn't pip
we couldn't pip
you couldn't pip
they couldn't pip 	I couldn't be pipping
you couldn't be pipping
he couldn't be pipping
we couldn't be pipping
you couldn't be pipping
they couldn't be pipping	I couldn't have pipped
you couldn't have pipped
he couldn't have pipped
we couldn't have pipped
you couldn't have pipped
they couldn't have pipped	I couldn't have been pipping
you couldn't have been pipping
he couldn't have been pipping
we couldn't have been pipping
you couldn't have been pipping
they couldn't have been pipping	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I pip?
could you pip?
could he pip?
could we pip?
could you pip?
could they pip? 	could I be pipping?
could you be pipping?
could he be pipping?
could we be pipping?
could you be pipping?
could they be pipping? 	could I have pipped?
could you have pipped?
could he have pipped?
could we have pipped?
could you have pipped?
could they have pipped? 	could I have been pipping?
could you have been pipping?
could he have been pipping?
could we have been pipping?
could you have been pipping?
could they have been pipping? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I pip?
couldn't you pip?
couldn't he pip?
couldn't we pip?
couldn't you pip?
couldn't they pip? 	couldn't I be pipping?
couldn't you be pipping?
couldn't he be pipping?
couldn't we be pipping?
couldn't you be pipping?
couldn't they be pipping? 	couldn't I have pipped?
couldn't you have pipped?
couldn't he have pipped?
couldn't we have pipped?
couldn't you have pipped?
couldn't they have pipped? 	couldn't I have been pipping?
couldn't you have been pipping?
couldn't he have been pipping?
couldn't we have been pipping?
couldn't you have been pipping?
couldn't they have been pipping?