could siphon
Regular verb: siphon - siphoned- siphoned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could siphon
you could siphon
she could siphon
we could siphon
you could siphon
they could siphon 	I could be siphoning
you could be siphoning
she could be siphoning
we could be siphoning
you could be siphoning
they could be siphoning	I could have siphoned
you could have siphoned
she could have siphoned
we could have siphoned
you could have siphoned
they could have siphoned	I could have been siphoning
you could have been siphoning
she could have been siphoning
we could have been siphoning
you could have been siphoning
they could have been siphoning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not siphon
you could not siphon
she could not siphon
we could not siphon
you could not siphon
they could not siphon 	I could not be siphoning
you could not be siphoning
she could not be siphoning
we could not be siphoning
you could not be siphoning
they could not be siphoning	I could not have siphoned
you could not have siphoned
she could not have siphoned
we could not have siphoned
you could not have siphoned
they could not have siphoned	I could not have been siphoning
you could not have been siphoning
she could not have been siphoning
we could not have been siphoning
you could not have been siphoning
they could not have been siphoning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I siphon?
could you siphon?
could she siphon?
could we siphon?
could you siphon?
could they siphon? 	could I be siphoning?
could you be siphoning?
could she be siphoning?
could we be siphoning?
could you be siphoning?
could they be siphoning? 	could I have siphoned?
could you have siphoned?
could she have siphoned?
could we have siphoned?
could you have siphoned?
could they have siphoned? 	could I have been siphoning?
could you have been siphoning?
could she have been siphoning?
could we have been siphoning?
could you have been siphoning?
could they have been siphoning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not siphon?
could you not siphon?
could she not siphon?
could we not siphon?
could you not siphon?
could they not siphon? 	could I not be siphoning?
could you not be siphoning?
could she not be siphoning?
could we not be siphoning?
could you not be siphoning?
could they not be siphoning? 	could I not have siphoned?
could you not have siphoned?
could she not have siphoned?
could we not have siphoned?
could you not have siphoned?
could they not have siphoned? 	could I not have been siphoning?
could you not have been siphoning?
could she not have been siphoning?
could we not have been siphoning?
could you not have been siphoning?
could they not have been siphoning?