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