English verb conjugation
MUST EXTEND

Regular verb: extend - extended - extended

Affirmation

Simple form	V-ing form
I must extend you must extend she must extend we must extend you must extend they must extend	I must be extending you must be extending she 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 she 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 she 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 must not extend you must not extend she must not extend we must not extend you must not extend they must not extend	I must not be extending you must not be extending she must not be extending we must not be extending you must not be extending they must not be extending
Perfect	V-ing perfect
I must not have extended you must not have extended she must not have extended we must not have extended you must not have extended they must not have extended	I must not have been extending you must not have been extending she must not have been extending we must not have been extending you must not have been extending they must not have been extending

Interrogative form

Simple form	V-ing form
must I extend? must you extend? must she extend? must we extend? must you extend? must they extend?	must I be extending? must you be extending? must she 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 she 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 she 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
must I not extend? must you not extend? must she not extend? must we not extend? must you not extend? must they not extend?	must I not be extending? must you not be extending? must she not be extending? must we not be extending? must you not be extending? must they not be extending?
Perfect	V-ing perfect
must I not have extended? must you not have extended? must she not have extended? must we not have extended? must you not have extended? must they not have extended?	must I not have been extending? must you not have been extending? must she not have been extending? must we not have been extending? must you not have been extending? must they not have been extending?