I could wait you could wait she could wait we could wait you could wait they could wait
V-ing form
I could be waiting you could be waiting she could be waiting we could be waiting you could be waiting they could be waiting
Perfect
I could have waited you could have waited she 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 she could have been waiting we could have been waiting you could have been waiting they could have been waiting
Negation
Simple form
I couldn't wait you couldn't wait she couldn't wait we couldn't wait you couldn't wait they couldn't wait
V-ing form
I couldn't be waiting you couldn't be waiting she couldn't be waiting we couldn't be waiting you couldn't be waiting they couldn't be waiting
Perfect
I couldn't have waited you couldn't have waited she couldn't have waited we couldn't have waited you couldn't have waited they couldn't have waited
V-ing perfect
I couldn't have been waiting you couldn't have been waiting she couldn't have been waiting we couldn't have been waiting you couldn't have been waiting they couldn't have been waiting
Interrogative form
Simple form
could I wait? could you wait? could she wait? could we wait? could you wait? could they wait?
V-ing form
could I be waiting? could you be waiting? could she be waiting? could we be waiting? could you be waiting? could they be waiting?
Perfect
could I have waited? could you have waited? could she 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 she have been waiting? could we have been waiting? could you have been waiting? could they have been waiting?
Interro-negative form
Simple form
couldn't I wait? couldn't you wait? couldn't she wait? couldn't we wait? couldn't you wait? couldn't they wait?
V-ing form
couldn't I be waiting? couldn't you be waiting? couldn't she be waiting? couldn't we be waiting? couldn't you be waiting? couldn't they be waiting?
Perfect
couldn't I have waited? couldn't you have waited? couldn't she have waited? couldn't we have waited? couldn't you have waited? couldn't they have waited?
V-ing perfect
couldn't I have been waiting? couldn't you have been waiting? couldn't she have been waiting? couldn't we have been waiting? couldn't you have been waiting? couldn't they have been waiting?