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