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