I can billow you can billow she can billow we can billow you can billow they can billow
V-ing form
I can be billowing you can be billowing she can be billowing we can be billowing you can be billowing they can be billowing
Perfect
I can have billowed you can have billowed she can have billowed we can have billowed you can have billowed they can have billowed
V-ing perfect
I can have been billowing you can have been billowing she can have been billowing we can have been billowing you can have been billowing they can have been billowing
Negation
Simple form
I cannot billow you cannot billow she cannot billow we cannot billow you cannot billow they cannot billow
V-ing form
I cannot be billowing you cannot be billowing she cannot be billowing we cannot be billowing you cannot be billowing they cannot be billowing
Perfect
I cannot have billowed you cannot have billowed she cannot have billowed we cannot have billowed you cannot have billowed they cannot have billowed
V-ing perfect
I cannot have been billowing you cannot have been billowing she cannot have been billowing we cannot have been billowing you cannot have been billowing they cannot have been billowing
Interrogative form
Simple form
can I billow? can you billow? can she billow? can we billow? can you billow? can they billow?
V-ing form
can I be billowing? can you be billowing? can she be billowing? can we be billowing? can you be billowing? can they be billowing?
Perfect
can I have billowed? can you have billowed? can she have billowed? can we have billowed? can you have billowed? can they have billowed?
V-ing perfect
can I have been billowing? can you have been billowing? can she have been billowing? can we have been billowing? can you have been billowing? can they have been billowing?
Interro-negative form
Simple form
can I not billow? can you not billow? can she not billow? can we not billow? can you not billow? can they not billow?
V-ing form
can I not be billowing? can you not be billowing? can she not be billowing? can we not be billowing? can you not be billowing? can they not be billowing?
Perfect
can I not have billowed? can you not have billowed? can she not have billowed? can we not have billowed? can you not have billowed? can they not have billowed?
V-ing perfect
can I not have been billowing? can you not have been billowing? can she not have been billowing? can we not have been billowing? can you not have been billowing? can they not have been billowing?