English verb conjugation
CAN WEAKEN

Regular verb: weaken - weakened - weakened

Affirmation

Simple form	V-ing form
I can weaken you can weaken he can weaken we can weaken you can weaken they can weaken	I can be weakening you can be weakening he can be weakening we can be weakening you can be weakening they can be weakening
Perfect	V-ing perfect
I can have weakened you can have weakened he can have weakened we can have weakened you can have weakened they can have weakened	I can have been weakening you can have been weakening he can have been weakening we can have been weakening you can have been weakening they can have been weakening

Negation

Simple form	V-ing form
I can't weaken you can't weaken he can't weaken we can't weaken you can't weaken they can't weaken	I can't be weakening you can't be weakening he can't be weakening we can't be weakening you can't be weakening they can't be weakening
Perfect	V-ing perfect
I can't have weakened you can't have weakened he can't have weakened we can't have weakened you can't have weakened they can't have weakened	I can't have been weakening you can't have been weakening he can't have been weakening we can't have been weakening you can't have been weakening they can't have been weakening

Interrogative form

Simple form	V-ing form
can I weaken? can you weaken? can he weaken? can we weaken? can you weaken? can they weaken?	can I be weakening? can you be weakening? can he be weakening? can we be weakening? can you be weakening? can they be weakening?
Perfect	V-ing perfect
can I have weakened? can you have weakened? can he have weakened? can we have weakened? can you have weakened? can they have weakened?	can I have been weakening? can you have been weakening? can he have been weakening? can we have been weakening? can you have been weakening? can they have been weakening?

Interro-negative form

Simple form	V-ing form
can't I weaken? can't you weaken? can't he weaken? can't we weaken? can't you weaken? can't they weaken?	can't I be weakening? can't you be weakening? can't he be weakening? can't we be weakening? can't you be weakening? can't they be weakening?
Perfect	V-ing perfect
can't I have weakened? can't you have weakened? can't he have weakened? can't we have weakened? can't you have weakened? can't they have weakened?	can't I have been weakening? can't you have been weakening? can't he have been weakening? can't we have been weakening? can't you have been weakening? can't they have been weakening?