I could wait you could wait he could wait we could wait you could wait they could wait
V-ing form
I could be waiting you could be waiting he could be waiting we could be waiting you could be waiting they could be waiting
Perfect
I could have waited you could have waited he could have waited we could have waited you could have waited they could have waited
V-ing perfect
I could have been waiting you could have been waiting he could have been waiting we could have been waiting you could have been waiting they could have been waiting
Negation
Simple form
I could not wait you could not wait he could not wait we could not wait you could not wait they could not wait
V-ing form
I could not be waiting you could not be waiting he could not be waiting we could not be waiting you could not be waiting they could not be waiting
Perfect
I could not have waited you could not have waited he could not have waited we could not have waited you could not have waited they could not have waited
V-ing perfect
I could not have been waiting you could not have been waiting he could not have been waiting we could not have been waiting you could not have been waiting they could not have been waiting
Interrogative form
Simple form
could I wait? could you wait? could he wait? could we wait? could you wait? could they wait?
V-ing form
could I be waiting? could you be waiting? could he be waiting? could we be waiting? could you be waiting? could they be waiting?
Perfect
could I have waited? could you have waited? could he have waited? could we have waited? could you have waited? could they have waited?
V-ing perfect
could I have been waiting? could you have been waiting? could he have been waiting? could we have been waiting? could you have been waiting? could they have been waiting?
Interro-negative form
Simple form
could I not wait? could you not wait? could he not wait? could we not wait? could you not wait? could they not wait?
V-ing form
could I not be waiting? could you not be waiting? could he not be waiting? could we not be waiting? could you not be waiting? could they not be waiting?
Perfect
could I not have waited? could you not have waited? could he not have waited? could we not have waited? could you not have waited? could they not have waited?
V-ing perfect
could I not have been waiting? could you not have been waiting? could he not have been waiting? could we not have been waiting? could you not have been waiting? could they not have been waiting?