English verb conjugation
COULD WEAKEN

Regular verb: weaken - weakened - weakened

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

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