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