I could saw you could saw she could saw we could saw you could saw they could saw
V-ing form
I could be sawing you could be sawing she could be sawing we could be sawing you could be sawing they could be sawing
Perfect
I could have sawed, sawn you could have sawed, sawn she could have sawed, sawn we could have sawed, sawn you could have sawed, sawn they could have sawed, sawn
V-ing perfect
I could have been sawing you could have been sawing she could have been sawing we could have been sawing you could have been sawing they could have been sawing
Negation
Simple form
I couldn't saw you couldn't saw she couldn't saw we couldn't saw you couldn't saw they couldn't saw
V-ing form
I couldn't be sawing you couldn't be sawing she couldn't be sawing we couldn't be sawing you couldn't be sawing they couldn't be sawing
Perfect
I couldn't have sawed, sawn you couldn't have sawed, sawn she couldn't have sawed, sawn we couldn't have sawed, sawn you couldn't have sawed, sawn they couldn't have sawed, sawn
V-ing perfect
I couldn't have been sawing you couldn't have been sawing she couldn't have been sawing we couldn't have been sawing you couldn't have been sawing they couldn't have been sawing
Interrogative form
Simple form
could I saw? could you saw? could she saw? could we saw? could you saw? could they saw?
V-ing form
could I be sawing? could you be sawing? could she be sawing? could we be sawing? could you be sawing? could they be sawing?
Perfect
could I have sawed, sawn? could you have sawed, sawn? could she have sawed, sawn? could we have sawed, sawn? could you have sawed, sawn? could they have sawed, sawn?
V-ing perfect
could I have been sawing? could you have been sawing? could she have been sawing? could we have been sawing? could you have been sawing? could they have been sawing?
Interro-negative form
Simple form
couldn't I saw? couldn't you saw? couldn't she saw? couldn't we saw? couldn't you saw? couldn't they saw?
V-ing form
couldn't I be sawing? couldn't you be sawing? couldn't she be sawing? couldn't we be sawing? couldn't you be sawing? couldn't they be sawing?
Perfect
couldn't I have sawed, sawn? couldn't you have sawed, sawn? couldn't she have sawed, sawn? couldn't we have sawed, sawn? couldn't you have sawed, sawn? couldn't they have sawed, sawn?
V-ing perfect
couldn't I have been sawing? couldn't you have been sawing? couldn't she have been sawing? couldn't we have been sawing? couldn't you have been sawing? couldn't they have been sawing?