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