I can reef you can reef she can reef we can reef you can reef they can reef
V-ing form
I can be reefing you can be reefing she can be reefing we can be reefing you can be reefing they can be reefing
Perfect
I can have reefed you can have reefed she can have reefed we can have reefed you can have reefed they can have reefed
V-ing perfect
I can have been reefing you can have been reefing she can have been reefing we can have been reefing you can have been reefing they can have been reefing
Negation
Simple form
I cannot reef you cannot reef she cannot reef we cannot reef you cannot reef they cannot reef
V-ing form
I cannot be reefing you cannot be reefing she cannot be reefing we cannot be reefing you cannot be reefing they cannot be reefing
Perfect
I cannot have reefed you cannot have reefed she cannot have reefed we cannot have reefed you cannot have reefed they cannot have reefed
V-ing perfect
I cannot have been reefing you cannot have been reefing she cannot have been reefing we cannot have been reefing you cannot have been reefing they cannot have been reefing
Interrogative form
Simple form
can I reef? can you reef? can she reef? can we reef? can you reef? can they reef?
V-ing form
can I be reefing? can you be reefing? can she be reefing? can we be reefing? can you be reefing? can they be reefing?
Perfect
can I have reefed? can you have reefed? can she have reefed? can we have reefed? can you have reefed? can they have reefed?
V-ing perfect
can I have been reefing? can you have been reefing? can she have been reefing? can we have been reefing? can you have been reefing? can they have been reefing?
Interro-negative form
Simple form
can I not reef? can you not reef? can she not reef? can we not reef? can you not reef? can they not reef?
V-ing form
can I not be reefing? can you not be reefing? can she not be reefing? can we not be reefing? can you not be reefing? can they not be reefing?
Perfect
can I not have reefed? can you not have reefed? can she not have reefed? can we not have reefed? can you not have reefed? can they not have reefed?
V-ing perfect
can I not have been reefing? can you not have been reefing? can she not have been reefing? can we not have been reefing? can you not have been reefing? can they not have been reefing?