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