English verb conjugation
COULD UNBOX

Regular verb: unbox - unboxed - unboxed

Affirmation

Simple form	V-ing form
I could unbox you could unbox he could unbox we could unbox you could unbox they could unbox	I could be unboxing you could be unboxing he could be unboxing we could be unboxing you could be unboxing they could be unboxing
Perfect	V-ing perfect
I could have unboxed you could have unboxed he could have unboxed we could have unboxed you could have unboxed they could have unboxed	I could have been unboxing you could have been unboxing he could have been unboxing we could have been unboxing you could have been unboxing they could have been unboxing

Negation

Simple form	V-ing form
I couldn't unbox you couldn't unbox he couldn't unbox we couldn't unbox you couldn't unbox they couldn't unbox	I couldn't be unboxing you couldn't be unboxing he couldn't be unboxing we couldn't be unboxing you couldn't be unboxing they couldn't be unboxing
Perfect	V-ing perfect
I couldn't have unboxed you couldn't have unboxed he couldn't have unboxed we couldn't have unboxed you couldn't have unboxed they couldn't have unboxed	I couldn't have been unboxing you couldn't have been unboxing he couldn't have been unboxing we couldn't have been unboxing you couldn't have been unboxing they couldn't have been unboxing

Interrogative form

Simple form	V-ing form
could I unbox? could you unbox? could he unbox? could we unbox? could you unbox? could they unbox?	could I be unboxing? could you be unboxing? could he be unboxing? could we be unboxing? could you be unboxing? could they be unboxing?
Perfect	V-ing perfect
could I have unboxed? could you have unboxed? could he have unboxed? could we have unboxed? could you have unboxed? could they have unboxed?	could I have been unboxing? could you have been unboxing? could he have been unboxing? could we have been unboxing? could you have been unboxing? could they have been unboxing?

Interro-negative form

Simple form	V-ing form
couldn't I unbox? couldn't you unbox? couldn't he unbox? couldn't we unbox? couldn't you unbox? couldn't they unbox?	couldn't I be unboxing? couldn't you be unboxing? couldn't he be unboxing? couldn't we be unboxing? couldn't you be unboxing? couldn't they be unboxing?
Perfect	V-ing perfect
couldn't I have unboxed? couldn't you have unboxed? couldn't he have unboxed? couldn't we have unboxed? couldn't you have unboxed? couldn't they have unboxed?	couldn't I have been unboxing? couldn't you have been unboxing? couldn't he have been unboxing? couldn't we have been unboxing? couldn't you have been unboxing? couldn't they have been unboxing?