I can wall you can wall he can wall we can wall you can wall they can wall
V-ing form
I can be walling you can be walling he can be walling we can be walling you can be walling they can be walling
Perfect
I can have walled you can have walled he can have walled we can have walled you can have walled they can have walled
V-ing perfect
I can have been walling you can have been walling he can have been walling we can have been walling you can have been walling they can have been walling
Negation
Simple form
I cannot wall you cannot wall he cannot wall we cannot wall you cannot wall they cannot wall
V-ing form
I cannot be walling you cannot be walling he cannot be walling we cannot be walling you cannot be walling they cannot be walling
Perfect
I cannot have walled you cannot have walled he cannot have walled we cannot have walled you cannot have walled they cannot have walled
V-ing perfect
I cannot have been walling you cannot have been walling he cannot have been walling we cannot have been walling you cannot have been walling they cannot have been walling
Interrogative form
Simple form
can I wall? can you wall? can he wall? can we wall? can you wall? can they wall?
V-ing form
can I be walling? can you be walling? can he be walling? can we be walling? can you be walling? can they be walling?
Perfect
can I have walled? can you have walled? can he have walled? can we have walled? can you have walled? can they have walled?
V-ing perfect
can I have been walling? can you have been walling? can he have been walling? can we have been walling? can you have been walling? can they have been walling?
Interro-negative form
Simple form
can I not wall? can you not wall? can he not wall? can we not wall? can you not wall? can they not wall?
V-ing form
can I not be walling? can you not be walling? can he not be walling? can we not be walling? can you not be walling? can they not be walling?
Perfect
can I not have walled? can you not have walled? can he not have walled? can we not have walled? can you not have walled? can they not have walled?
V-ing perfect
can I not have been walling? can you not have been walling? can he not have been walling? can we not have been walling? can you not have been walling? can they not have been walling?