English verb conjugation
CAN STEM

Regular verb: stem - stemmed - stemmed

Affirmation

Simple form	V-ing form
I can stem you can stem he can stem we can stem you can stem they can stem	I can be stemming you can be stemming he can be stemming we can be stemming you can be stemming they can be stemming
Perfect	V-ing perfect
I can have stemmed you can have stemmed he can have stemmed we can have stemmed you can have stemmed they can have stemmed	I can have been stemming you can have been stemming he can have been stemming we can have been stemming you can have been stemming they can have been stemming

Negation

Simple form	V-ing form
I can't stem you can't stem he can't stem we can't stem you can't stem they can't stem	I can't be stemming you can't be stemming he can't be stemming we can't be stemming you can't be stemming they can't be stemming
Perfect	V-ing perfect
I can't have stemmed you can't have stemmed he can't have stemmed we can't have stemmed you can't have stemmed they can't have stemmed	I can't have been stemming you can't have been stemming he can't have been stemming we can't have been stemming you can't have been stemming they can't have been stemming

Interrogative form

Simple form	V-ing form
can I stem? can you stem? can he stem? can we stem? can you stem? can they stem?	can I be stemming? can you be stemming? can he be stemming? can we be stemming? can you be stemming? can they be stemming?
Perfect	V-ing perfect
can I have stemmed? can you have stemmed? can he have stemmed? can we have stemmed? can you have stemmed? can they have stemmed?	can I have been stemming? can you have been stemming? can he have been stemming? can we have been stemming? can you have been stemming? can they have been stemming?

Interro-negative form

Simple form	V-ing form
can't I stem? can't you stem? can't he stem? can't we stem? can't you stem? can't they stem?	can't I be stemming? can't you be stemming? can't he be stemming? can't we be stemming? can't you be stemming? can't they be stemming?
Perfect	V-ing perfect
can't I have stemmed? can't you have stemmed? can't he have stemmed? can't we have stemmed? can't you have stemmed? can't they have stemmed?	can't I have been stemming? can't you have been stemming? can't he have been stemming? can't we have been stemming? can't you have been stemming? can't they have been stemming?