could postmark
Regular verb: postmark - postmarked- postmarked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could postmark
you could postmark
she could postmark
we could postmark
you could postmark
they could postmark 	I could be postmarking
you could be postmarking
she could be postmarking
we could be postmarking
you could be postmarking
they could be postmarking	I could have postmarked
you could have postmarked
she could have postmarked
we could have postmarked
you could have postmarked
they could have postmarked	I could have been postmarking
you could have been postmarking
she could have been postmarking
we could have been postmarking
you could have been postmarking
they could have been postmarking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't postmark
you couldn't postmark
she couldn't postmark
we couldn't postmark
you couldn't postmark
they couldn't postmark 	I couldn't be postmarking
you couldn't be postmarking
she couldn't be postmarking
we couldn't be postmarking
you couldn't be postmarking
they couldn't be postmarking	I couldn't have postmarked
you couldn't have postmarked
she couldn't have postmarked
we couldn't have postmarked
you couldn't have postmarked
they couldn't have postmarked	I couldn't have been postmarking
you couldn't have been postmarking
she couldn't have been postmarking
we couldn't have been postmarking
you couldn't have been postmarking
they couldn't have been postmarking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I postmark?
could you postmark?
could she postmark?
could we postmark?
could you postmark?
could they postmark? 	could I be postmarking?
could you be postmarking?
could she be postmarking?
could we be postmarking?
could you be postmarking?
could they be postmarking? 	could I have postmarked?
could you have postmarked?
could she have postmarked?
could we have postmarked?
could you have postmarked?
could they have postmarked? 	could I have been postmarking?
could you have been postmarking?
could she have been postmarking?
could we have been postmarking?
could you have been postmarking?
could they have been postmarking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I postmark?
couldn't you postmark?
couldn't she postmark?
couldn't we postmark?
couldn't you postmark?
couldn't they postmark? 	couldn't I be postmarking?
couldn't you be postmarking?
couldn't she be postmarking?
couldn't we be postmarking?
couldn't you be postmarking?
couldn't they be postmarking? 	couldn't I have postmarked?
couldn't you have postmarked?
couldn't she have postmarked?
couldn't we have postmarked?
couldn't you have postmarked?
couldn't they have postmarked? 	couldn't I have been postmarking?
couldn't you have been postmarking?
couldn't she have been postmarking?
couldn't we have been postmarking?
couldn't you have been postmarking?
couldn't they have been postmarking?