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