I must belabour you must belabour she must belabour we must belabour you must belabour they must belabour
V-ing form
I must be belabouring you must be belabouring she must be belabouring we must be belabouring you must be belabouring they must be belabouring
Perfect
I must have belaboured you must have belaboured she must have belaboured we must have belaboured you must have belaboured they must have belaboured
V-ing perfect
I must have been belabouring you must have been belabouring she must have been belabouring we must have been belabouring you must have been belabouring they must have been belabouring
Negation
Simple form
I must not belabour you must not belabour she must not belabour we must not belabour you must not belabour they must not belabour
V-ing form
I must not be belabouring you must not be belabouring she must not be belabouring we must not be belabouring you must not be belabouring they must not be belabouring
Perfect
I must not have belaboured you must not have belaboured she must not have belaboured we must not have belaboured you must not have belaboured they must not have belaboured
V-ing perfect
I must not have been belabouring you must not have been belabouring she must not have been belabouring we must not have been belabouring you must not have been belabouring they must not have been belabouring
Interrogative form
Simple form
must I belabour? must you belabour? must she belabour? must we belabour? must you belabour? must they belabour?
V-ing form
must I be belabouring? must you be belabouring? must she be belabouring? must we be belabouring? must you be belabouring? must they be belabouring?
Perfect
must I have belaboured? must you have belaboured? must she have belaboured? must we have belaboured? must you have belaboured? must they have belaboured?
V-ing perfect
must I have been belabouring? must you have been belabouring? must she have been belabouring? must we have been belabouring? must you have been belabouring? must they have been belabouring?
Interro-negative form
Simple form
must I not belabour? must you not belabour? must she not belabour? must we not belabour? must you not belabour? must they not belabour?
V-ing form
must I not be belabouring? must you not be belabouring? must she not be belabouring? must we not be belabouring? must you not be belabouring? must they not be belabouring?
Perfect
must I not have belaboured? must you not have belaboured? must she not have belaboured? must we not have belaboured? must you not have belaboured? must they not have belaboured?
V-ing perfect
must I not have been belabouring? must you not have been belabouring? must she not have been belabouring? must we not have been belabouring? must you not have been belabouring? must they not have been belabouring?