English verb conjugation
MUST IMPAIR

Regular verb: impair - impaired - impaired

Affirmation

Simple form	V-ing form
I must impair you must impair she must impair we must impair you must impair they must impair	I must be impairing you must be impairing she 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 she 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 she 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 she 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 she 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 she 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 she 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 she impair? must we impair? must you impair? must they impair?	must I be impairing? must you be impairing? must she 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 she 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 she 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 she 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 she 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 she 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 she have been impairing? mustn't we have been impairing? mustn't you have been impairing? mustn't they have been impairing?