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 can't bubble you can't bubble he can't bubble we can't bubble you can't bubble they can't bubble
V-ing form
I can't be bubbling you can't be bubbling he can't be bubbling we can't be bubbling you can't be bubbling they can't be bubbling
Perfect
I can't have bubbled you can't have bubbled he can't have bubbled we can't have bubbled you can't have bubbled they can't have bubbled
V-ing perfect
I can't have been bubbling you can't have been bubbling he can't have been bubbling we can't have been bubbling you can't have been bubbling they can't 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't I bubble? can't you bubble? can't he bubble? can't we bubble? can't you bubble? can't they bubble?
V-ing form
can't I be bubbling? can't you be bubbling? can't he be bubbling? can't we be bubbling? can't you be bubbling? can't they be bubbling?
Perfect
can't I have bubbled? can't you have bubbled? can't he have bubbled? can't we have bubbled? can't you have bubbled? can't they have bubbled?
V-ing perfect
can't I have been bubbling? can't you have been bubbling? can't he have been bubbling? can't we have been bubbling? can't you have been bubbling? can't they have been bubbling?