English verb conjugation
MUST IMPAIR

Regular verb: impair - impaired - impaired

Affirmation

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

Negation

Simple form	V-ing form
I must not impair you must not impair he must not impair we must not impair you must not impair they must not impair	I must not be impairing you must not be impairing he must not be impairing we must not be impairing you must not be impairing they must not be impairing
Perfect	V-ing perfect
I must not have impaired you must not have impaired he must not have impaired we must not have impaired you must not have impaired they must not have impaired	I must not have been impairing you must not have been impairing he must not have been impairing we must not have been impairing you must not have been impairing they must not have been impairing

Interrogative form

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

Interro-negative form

Simple form	V-ing form
must I not impair? must you not impair? must he not impair? must we not impair? must you not impair? must they not impair?	must I not be impairing? must you not be impairing? must he not be impairing? must we not be impairing? must you not be impairing? must they not be impairing?
Perfect	V-ing perfect
must I not have impaired? must you not have impaired? must he not have impaired? must we not have impaired? must you not have impaired? must they not have impaired?	must I not have been impairing? must you not have been impairing? must he not have been impairing? must we not have been impairing? must you not have been impairing? must they not have been impairing?