I could affix you could affix she could affix we could affix you could affix they could affix
V-ing form
I could be affixing you could be affixing she could be affixing we could be affixing you could be affixing they could be affixing
Perfect
I could have affixed you could have affixed she could have affixed we could have affixed you could have affixed they could have affixed
V-ing perfect
I could have been affixing you could have been affixing she could have been affixing we could have been affixing you could have been affixing they could have been affixing
Negation
Simple form
I couldn't affix you couldn't affix she couldn't affix we couldn't affix you couldn't affix they couldn't affix
V-ing form
I couldn't be affixing you couldn't be affixing she couldn't be affixing we couldn't be affixing you couldn't be affixing they couldn't be affixing
Perfect
I couldn't have affixed you couldn't have affixed she couldn't have affixed we couldn't have affixed you couldn't have affixed they couldn't have affixed
V-ing perfect
I couldn't have been affixing you couldn't have been affixing she couldn't have been affixing we couldn't have been affixing you couldn't have been affixing they couldn't have been affixing
Interrogative form
Simple form
could I affix? could you affix? could she affix? could we affix? could you affix? could they affix?
V-ing form
could I be affixing? could you be affixing? could she be affixing? could we be affixing? could you be affixing? could they be affixing?
Perfect
could I have affixed? could you have affixed? could she have affixed? could we have affixed? could you have affixed? could they have affixed?
V-ing perfect
could I have been affixing? could you have been affixing? could she have been affixing? could we have been affixing? could you have been affixing? could they have been affixing?
Interro-negative form
Simple form
couldn't I affix? couldn't you affix? couldn't she affix? couldn't we affix? couldn't you affix? couldn't they affix?
V-ing form
couldn't I be affixing? couldn't you be affixing? couldn't she be affixing? couldn't we be affixing? couldn't you be affixing? couldn't they be affixing?
Perfect
couldn't I have affixed? couldn't you have affixed? couldn't she have affixed? couldn't we have affixed? couldn't you have affixed? couldn't they have affixed?
V-ing perfect
couldn't I have been affixing? couldn't you have been affixing? couldn't she have been affixing? couldn't we have been affixing? couldn't you have been affixing? couldn't they have been affixing?