I could tuck you could tuck he could tuck we could tuck you could tuck they could tuck
V-ing form
I could be tucking you could be tucking he could be tucking we could be tucking you could be tucking they could be tucking
Perfect
I could have tucked you could have tucked he could have tucked we could have tucked you could have tucked they could have tucked
V-ing perfect
I could have been tucking you could have been tucking he could have been tucking we could have been tucking you could have been tucking they could have been tucking
Negation
Simple form
I couldn't tuck you couldn't tuck he couldn't tuck we couldn't tuck you couldn't tuck they couldn't tuck
V-ing form
I couldn't be tucking you couldn't be tucking he couldn't be tucking we couldn't be tucking you couldn't be tucking they couldn't be tucking
Perfect
I couldn't have tucked you couldn't have tucked he couldn't have tucked we couldn't have tucked you couldn't have tucked they couldn't have tucked
V-ing perfect
I couldn't have been tucking you couldn't have been tucking he couldn't have been tucking we couldn't have been tucking you couldn't have been tucking they couldn't have been tucking
Interrogative form
Simple form
could I tuck? could you tuck? could he tuck? could we tuck? could you tuck? could they tuck?
V-ing form
could I be tucking? could you be tucking? could he be tucking? could we be tucking? could you be tucking? could they be tucking?
Perfect
could I have tucked? could you have tucked? could he have tucked? could we have tucked? could you have tucked? could they have tucked?
V-ing perfect
could I have been tucking? could you have been tucking? could he have been tucking? could we have been tucking? could you have been tucking? could they have been tucking?
Interro-negative form
Simple form
couldn't I tuck? couldn't you tuck? couldn't he tuck? couldn't we tuck? couldn't you tuck? couldn't they tuck?
V-ing form
couldn't I be tucking? couldn't you be tucking? couldn't he be tucking? couldn't we be tucking? couldn't you be tucking? couldn't they be tucking?
Perfect
couldn't I have tucked? couldn't you have tucked? couldn't he have tucked? couldn't we have tucked? couldn't you have tucked? couldn't they have tucked?
V-ing perfect
couldn't I have been tucking? couldn't you have been tucking? couldn't he have been tucking? couldn't we have been tucking? couldn't you have been tucking? couldn't they have been tucking?