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