English verb conjugation
COULD IMPAIR

Regular verb: impair - impaired - impaired

Affirmation

Simple form	V-ing form
I could impair you could impair he could impair we could impair you could impair they could impair	I could be impairing you could be impairing he could be impairing we could be impairing you could be impairing they could be impairing
Perfect	V-ing perfect
I could have impaired you could have impaired he could have impaired we could have impaired you could have impaired they could have impaired	I could have been impairing you could have been impairing he could have been impairing we could have been impairing you could have been impairing they could have been impairing

Negation

Simple form	V-ing form
I couldn't impair you couldn't impair he couldn't impair we couldn't impair you couldn't impair they couldn't impair	I couldn't be impairing you couldn't be impairing he couldn't be impairing we couldn't be impairing you couldn't be impairing they couldn't be impairing
Perfect	V-ing perfect
I couldn't have impaired you couldn't have impaired he couldn't have impaired we couldn't have impaired you couldn't have impaired they couldn't have impaired	I couldn't have been impairing you couldn't have been impairing he couldn't have been impairing we couldn't have been impairing you couldn't have been impairing they couldn't have been impairing

Interrogative form

Simple form	V-ing form
could I impair? could you impair? could he impair? could we impair? could you impair? could they impair?	could I be impairing? could you be impairing? could he be impairing? could we be impairing? could you be impairing? could they be impairing?
Perfect	V-ing perfect
could I have impaired? could you have impaired? could he have impaired? could we have impaired? could you have impaired? could they have impaired?	could I have been impairing? could you have been impairing? could he have been impairing? could we have been impairing? could you have been impairing? could they have been impairing?

Interro-negative form

Simple form	V-ing form
couldn't I impair? couldn't you impair? couldn't he impair? couldn't we impair? couldn't you impair? couldn't they impair?	couldn't I be impairing? couldn't you be impairing? couldn't he be impairing? couldn't we be impairing? couldn't you be impairing? couldn't they be impairing?
Perfect	V-ing perfect
couldn't I have impaired? couldn't you have impaired? couldn't he have impaired? couldn't we have impaired? couldn't you have impaired? couldn't they have impaired?	couldn't I have been impairing? couldn't you have been impairing? couldn't he have been impairing? couldn't we have been impairing? couldn't you have been impairing? couldn't they have been impairing?