English verb conjugation
MUST PROP

Regular verb: prop - propped - propped

Affirmation

Simple form	V-ing form
I must prop you must prop he must prop we must prop you must prop they must prop	I must be propping you must be propping he must be propping we must be propping you must be propping they must be propping
Perfect	V-ing perfect
I must have propped you must have propped he must have propped we must have propped you must have propped they must have propped	I must have been propping you must have been propping he must have been propping we must have been propping you must have been propping they must have been propping

Negation

Simple form	V-ing form
I mustn't prop you mustn't prop he mustn't prop we mustn't prop you mustn't prop they mustn't prop	I mustn't be propping you mustn't be propping he mustn't be propping we mustn't be propping you mustn't be propping they mustn't be propping
Perfect	V-ing perfect
I mustn't have propped you mustn't have propped he mustn't have propped we mustn't have propped you mustn't have propped they mustn't have propped	I mustn't have been propping you mustn't have been propping he mustn't have been propping we mustn't have been propping you mustn't have been propping they mustn't have been propping

Interrogative form

Simple form	V-ing form
must I prop? must you prop? must he prop? must we prop? must you prop? must they prop?	must I be propping? must you be propping? must he be propping? must we be propping? must you be propping? must they be propping?
Perfect	V-ing perfect
must I have propped? must you have propped? must he have propped? must we have propped? must you have propped? must they have propped?	must I have been propping? must you have been propping? must he have been propping? must we have been propping? must you have been propping? must they have been propping?

Interro-negative form

Simple form	V-ing form
mustn't I prop? mustn't you prop? mustn't he prop? mustn't we prop? mustn't you prop? mustn't they prop?	mustn't I be propping? mustn't you be propping? mustn't he be propping? mustn't we be propping? mustn't you be propping? mustn't they be propping?
Perfect	V-ing perfect
mustn't I have propped? mustn't you have propped? mustn't he have propped? mustn't we have propped? mustn't you have propped? mustn't they have propped?	mustn't I have been propping? mustn't you have been propping? mustn't he have been propping? mustn't we have been propping? mustn't you have been propping? mustn't they have been propping?