I can bubble you can bubble he can bubble we can bubble you can bubble they can bubble
V-ing form
I can be bubbling you can be bubbling he can be bubbling we can be bubbling you can be bubbling they can be bubbling
Perfect
I can have bubbled you can have bubbled he can have bubbled we can have bubbled you can have bubbled they can have bubbled
V-ing perfect
I can have been bubbling you can have been bubbling he can have been bubbling we can have been bubbling you can have been bubbling they can have been bubbling
Negation
Simple form
I cannot bubble you cannot bubble he cannot bubble we cannot bubble you cannot bubble they cannot bubble
V-ing form
I cannot be bubbling you cannot be bubbling he cannot be bubbling we cannot be bubbling you cannot be bubbling they cannot be bubbling
Perfect
I cannot have bubbled you cannot have bubbled he cannot have bubbled we cannot have bubbled you cannot have bubbled they cannot have bubbled
V-ing perfect
I cannot have been bubbling you cannot have been bubbling he cannot have been bubbling we cannot have been bubbling you cannot have been bubbling they cannot have been bubbling
Interrogative form
Simple form
can I bubble? can you bubble? can he bubble? can we bubble? can you bubble? can they bubble?
V-ing form
can I be bubbling? can you be bubbling? can he be bubbling? can we be bubbling? can you be bubbling? can they be bubbling?
Perfect
can I have bubbled? can you have bubbled? can he have bubbled? can we have bubbled? can you have bubbled? can they have bubbled?
V-ing perfect
can I have been bubbling? can you have been bubbling? can he have been bubbling? can we have been bubbling? can you have been bubbling? can they have been bubbling?
Interro-negative form
Simple form
can I not bubble? can you not bubble? can he not bubble? can we not bubble? can you not bubble? can they not bubble?
V-ing form
can I not be bubbling? can you not be bubbling? can he not be bubbling? can we not be bubbling? can you not be bubbling? can they not be bubbling?
Perfect
can I not have bubbled? can you not have bubbled? can he not have bubbled? can we not have bubbled? can you not have bubbled? can they not have bubbled?
V-ing perfect
can I not have been bubbling? can you not have been bubbling? can he not have been bubbling? can we not have been bubbling? can you not have been bubbling? can they not have been bubbling?