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