English verb conjugation
CAN STRENGTHEN

Regular verb: strengthen - strengthened - strengthened

Affirmation

Simple form	V-ing form
I can strengthen you can strengthen he can strengthen we can strengthen you can strengthen they can strengthen	I can be strengthening you can be strengthening he can be strengthening we can be strengthening you can be strengthening they can be strengthening
Perfect	V-ing perfect
I can have strengthened you can have strengthened he can have strengthened we can have strengthened you can have strengthened they can have strengthened	I can have been strengthening you can have been strengthening he can have been strengthening we can have been strengthening you can have been strengthening they can have been strengthening

Negation

Simple form	V-ing form
I can't strengthen you can't strengthen he can't strengthen we can't strengthen you can't strengthen they can't strengthen	I can't be strengthening you can't be strengthening he can't be strengthening we can't be strengthening you can't be strengthening they can't be strengthening
Perfect	V-ing perfect
I can't have strengthened you can't have strengthened he can't have strengthened we can't have strengthened you can't have strengthened they can't have strengthened	I can't have been strengthening you can't have been strengthening he can't have been strengthening we can't have been strengthening you can't have been strengthening they can't have been strengthening

Interrogative form

Simple form	V-ing form
can I strengthen? can you strengthen? can he strengthen? can we strengthen? can you strengthen? can they strengthen?	can I be strengthening? can you be strengthening? can he be strengthening? can we be strengthening? can you be strengthening? can they be strengthening?
Perfect	V-ing perfect
can I have strengthened? can you have strengthened? can he have strengthened? can we have strengthened? can you have strengthened? can they have strengthened?	can I have been strengthening? can you have been strengthening? can he have been strengthening? can we have been strengthening? can you have been strengthening? can they have been strengthening?

Interro-negative form

Simple form	V-ing form
can't I strengthen? can't you strengthen? can't he strengthen? can't we strengthen? can't you strengthen? can't they strengthen?	can't I be strengthening? can't you be strengthening? can't he be strengthening? can't we be strengthening? can't you be strengthening? can't they be strengthening?
Perfect	V-ing perfect
can't I have strengthened? can't you have strengthened? can't he have strengthened? can't we have strengthened? can't you have strengthened? can't they have strengthened?	can't I have been strengthening? can't you have been strengthening? can't he have been strengthening? can't we have been strengthening? can't you have been strengthening? can't they have been strengthening?