I could adjoin you could adjoin he could adjoin we could adjoin you could adjoin they could adjoin
V-ing form
I could be adjoining you could be adjoining he could be adjoining we could be adjoining you could be adjoining they could be adjoining
Perfect
I could have adjoined you could have adjoined he could have adjoined we could have adjoined you could have adjoined they could have adjoined
V-ing perfect
I could have been adjoining you could have been adjoining he could have been adjoining we could have been adjoining you could have been adjoining they could have been adjoining
Negation
Simple form
I could not adjoin you could not adjoin he could not adjoin we could not adjoin you could not adjoin they could not adjoin
V-ing form
I could not be adjoining you could not be adjoining he could not be adjoining we could not be adjoining you could not be adjoining they could not be adjoining
Perfect
I could not have adjoined you could not have adjoined he could not have adjoined we could not have adjoined you could not have adjoined they could not have adjoined
V-ing perfect
I could not have been adjoining you could not have been adjoining he could not have been adjoining we could not have been adjoining you could not have been adjoining they could not have been adjoining
Interrogative form
Simple form
could I adjoin? could you adjoin? could he adjoin? could we adjoin? could you adjoin? could they adjoin?
V-ing form
could I be adjoining? could you be adjoining? could he be adjoining? could we be adjoining? could you be adjoining? could they be adjoining?
Perfect
could I have adjoined? could you have adjoined? could he have adjoined? could we have adjoined? could you have adjoined? could they have adjoined?
V-ing perfect
could I have been adjoining? could you have been adjoining? could he have been adjoining? could we have been adjoining? could you have been adjoining? could they have been adjoining?
Interro-negative form
Simple form
could I not adjoin? could you not adjoin? could he not adjoin? could we not adjoin? could you not adjoin? could they not adjoin?
V-ing form
could I not be adjoining? could you not be adjoining? could he not be adjoining? could we not be adjoining? could you not be adjoining? could they not be adjoining?
Perfect
could I not have adjoined? could you not have adjoined? could he not have adjoined? could we not have adjoined? could you not have adjoined? could they not have adjoined?
V-ing perfect
could I not have been adjoining? could you not have been adjoining? could he not have been adjoining? could we not have been adjoining? could you not have been adjoining? could they not have been adjoining?