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