English verb conjugation
CAN PROP

Regular verb: prop - propped - propped

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

Simple form	V-ing form
can I not prop? can you not prop? can he not prop? can we not prop? can you not prop? can they not prop?	can I not be propping? can you not be propping? can he not be propping? can we not be propping? can you not be propping? can they not be propping?
Perfect	V-ing perfect
can I not have propped? can you not have propped? can he not have propped? can we not have propped? can you not have propped? can they not have propped?	can I not have been propping? can you not have been propping? can he not have been propping? can we not have been propping? can you not have been propping? can they not have been propping?