English verb conjugation
MUST EXTEND

Regular verb: extend - extended - extended

Affirmation

Simple form	V-ing form
I must extend you must extend he must extend we must extend you must extend they must extend	I must be extending you must be extending he must be extending we must be extending you must be extending they must be extending
Perfect	V-ing perfect
I must have extended you must have extended he must have extended we must have extended you must have extended they must have extended	I must have been extending you must have been extending he must have been extending we must have been extending you must have been extending they must have been extending

Negation

Simple form	V-ing form
I mustn't extend you mustn't extend he mustn't extend we mustn't extend you mustn't extend they mustn't extend	I mustn't be extending you mustn't be extending he mustn't be extending we mustn't be extending you mustn't be extending they mustn't be extending
Perfect	V-ing perfect
I mustn't have extended you mustn't have extended he mustn't have extended we mustn't have extended you mustn't have extended they mustn't have extended	I mustn't have been extending you mustn't have been extending he mustn't have been extending we mustn't have been extending you mustn't have been extending they mustn't have been extending

Interrogative form

Simple form	V-ing form
must I extend? must you extend? must he extend? must we extend? must you extend? must they extend?	must I be extending? must you be extending? must he be extending? must we be extending? must you be extending? must they be extending?
Perfect	V-ing perfect
must I have extended? must you have extended? must he have extended? must we have extended? must you have extended? must they have extended?	must I have been extending? must you have been extending? must he have been extending? must we have been extending? must you have been extending? must they have been extending?

Interro-negative form

Simple form	V-ing form
mustn't I extend? mustn't you extend? mustn't he extend? mustn't we extend? mustn't you extend? mustn't they extend?	mustn't I be extending? mustn't you be extending? mustn't he be extending? mustn't we be extending? mustn't you be extending? mustn't they be extending?
Perfect	V-ing perfect
mustn't I have extended? mustn't you have extended? mustn't he have extended? mustn't we have extended? mustn't you have extended? mustn't they have extended?	mustn't I have been extending? mustn't you have been extending? mustn't he have been extending? mustn't we have been extending? mustn't you have been extending? mustn't they have been extending?