Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could expand sth you could expand sth he could expand sth we could expand sth you could expand sth they could expand sth
V-ing form
I could be expand sthing you could be expand sthing he could be expand sthing we could be expand sthing you could be expand sthing they could be expand sthing
Perfect
I could have expand sthed you could have expand sthed he could have expand sthed we could have expand sthed you could have expand sthed they could have expand sthed
V-ing perfect
I could have been expand sthing you could have been expand sthing he could have been expand sthing we could have been expand sthing you could have been expand sthing they could have been expand sthing
Negation
Simple form
I could not expand sth you could not expand sth he could not expand sth we could not expand sth you could not expand sth they could not expand sth
V-ing form
I could not be expand sthing you could not be expand sthing he could not be expand sthing we could not be expand sthing you could not be expand sthing they could not be expand sthing
Perfect
I could not have expand sthed you could not have expand sthed he could not have expand sthed we could not have expand sthed you could not have expand sthed they could not have expand sthed
V-ing perfect
I could not have been expand sthing you could not have been expand sthing he could not have been expand sthing we could not have been expand sthing you could not have been expand sthing they could not have been expand sthing
Interrogative form
Simple form
could I expand sth? could you expand sth? could he expand sth? could we expand sth? could you expand sth? could they expand sth?
V-ing form
could I be expand sthing? could you be expand sthing? could he be expand sthing? could we be expand sthing? could you be expand sthing? could they be expand sthing?
Perfect
could I have expand sthed? could you have expand sthed? could he have expand sthed? could we have expand sthed? could you have expand sthed? could they have expand sthed?
V-ing perfect
could I have been expand sthing? could you have been expand sthing? could he have been expand sthing? could we have been expand sthing? could you have been expand sthing? could they have been expand sthing?
Interro-negative form
Simple form
could I not expand sth? could you not expand sth? could he not expand sth? could we not expand sth? could you not expand sth? could they not expand sth?
V-ing form
could I not be expand sthing? could you not be expand sthing? could he not be expand sthing? could we not be expand sthing? could you not be expand sthing? could they not be expand sthing?
Perfect
could I not have expand sthed? could you not have expand sthed? could he not have expand sthed? could we not have expand sthed? could you not have expand sthed? could they not have expand sthed?
V-ing perfect
could I not have been expand sthing? could you not have been expand sthing? could he not have been expand sthing? could we not have been expand sthing? could you not have been expand sthing? could they not have been expand sthing?