could shadowbox
Regular verb: shadowbox - shadowboxed- shadowboxed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could shadowbox
you could shadowbox
she could shadowbox
we could shadowbox
you could shadowbox
they could shadowbox 	I could be shadowboxing
you could be shadowboxing
she could be shadowboxing
we could be shadowboxing
you could be shadowboxing
they could be shadowboxing	I could have shadowboxed
you could have shadowboxed
she could have shadowboxed
we could have shadowboxed
you could have shadowboxed
they could have shadowboxed	I could have been shadowboxing
you could have been shadowboxing
she could have been shadowboxing
we could have been shadowboxing
you could have been shadowboxing
they could have been shadowboxing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't shadowbox
you couldn't shadowbox
she couldn't shadowbox
we couldn't shadowbox
you couldn't shadowbox
they couldn't shadowbox 	I couldn't be shadowboxing
you couldn't be shadowboxing
she couldn't be shadowboxing
we couldn't be shadowboxing
you couldn't be shadowboxing
they couldn't be shadowboxing	I couldn't have shadowboxed
you couldn't have shadowboxed
she couldn't have shadowboxed
we couldn't have shadowboxed
you couldn't have shadowboxed
they couldn't have shadowboxed	I couldn't have been shadowboxing
you couldn't have been shadowboxing
she couldn't have been shadowboxing
we couldn't have been shadowboxing
you couldn't have been shadowboxing
they couldn't have been shadowboxing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I shadowbox?
could you shadowbox?
could she shadowbox?
could we shadowbox?
could you shadowbox?
could they shadowbox? 	could I be shadowboxing?
could you be shadowboxing?
could she be shadowboxing?
could we be shadowboxing?
could you be shadowboxing?
could they be shadowboxing? 	could I have shadowboxed?
could you have shadowboxed?
could she have shadowboxed?
could we have shadowboxed?
could you have shadowboxed?
could they have shadowboxed? 	could I have been shadowboxing?
could you have been shadowboxing?
could she have been shadowboxing?
could we have been shadowboxing?
could you have been shadowboxing?
could they have been shadowboxing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I shadowbox?
couldn't you shadowbox?
couldn't she shadowbox?
couldn't we shadowbox?
couldn't you shadowbox?
couldn't they shadowbox? 	couldn't I be shadowboxing?
couldn't you be shadowboxing?
couldn't she be shadowboxing?
couldn't we be shadowboxing?
couldn't you be shadowboxing?
couldn't they be shadowboxing? 	couldn't I have shadowboxed?
couldn't you have shadowboxed?
couldn't she have shadowboxed?
couldn't we have shadowboxed?
couldn't you have shadowboxed?
couldn't they have shadowboxed? 	couldn't I have been shadowboxing?
couldn't you have been shadowboxing?
couldn't she have been shadowboxing?
couldn't we have been shadowboxing?
couldn't you have been shadowboxing?
couldn't they have been shadowboxing?