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