I must lap you must lap he must lap we must lap you must lap they must lap
V-ing form
I must be lapping you must be lapping he must be lapping we must be lapping you must be lapping they must be lapping
Perfect
I must have lapped you must have lapped he must have lapped we must have lapped you must have lapped they must have lapped
V-ing perfect
I must have been lapping you must have been lapping he must have been lapping we must have been lapping you must have been lapping they must have been lapping
Negation
Simple form
I mustn't lap you mustn't lap he mustn't lap we mustn't lap you mustn't lap they mustn't lap
V-ing form
I mustn't be lapping you mustn't be lapping he mustn't be lapping we mustn't be lapping you mustn't be lapping they mustn't be lapping
Perfect
I mustn't have lapped you mustn't have lapped he mustn't have lapped we mustn't have lapped you mustn't have lapped they mustn't have lapped
V-ing perfect
I mustn't have been lapping you mustn't have been lapping he mustn't have been lapping we mustn't have been lapping you mustn't have been lapping they mustn't have been lapping
Interrogative form
Simple form
must I lap? must you lap? must he lap? must we lap? must you lap? must they lap?
V-ing form
must I be lapping? must you be lapping? must he be lapping? must we be lapping? must you be lapping? must they be lapping?
Perfect
must I have lapped? must you have lapped? must he have lapped? must we have lapped? must you have lapped? must they have lapped?
V-ing perfect
must I have been lapping? must you have been lapping? must he have been lapping? must we have been lapping? must you have been lapping? must they have been lapping?
Interro-negative form
Simple form
mustn't I lap? mustn't you lap? mustn't he lap? mustn't we lap? mustn't you lap? mustn't they lap?
V-ing form
mustn't I be lapping? mustn't you be lapping? mustn't he be lapping? mustn't we be lapping? mustn't you be lapping? mustn't they be lapping?
Perfect
mustn't I have lapped? mustn't you have lapped? mustn't he have lapped? mustn't we have lapped? mustn't you have lapped? mustn't they have lapped?
V-ing perfect
mustn't I have been lapping? mustn't you have been lapping? mustn't he have been lapping? mustn't we have been lapping? mustn't you have been lapping? mustn't they have been lapping?