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