English verb conjugation
MUST PIPE

Regular verb: pipe - piped - piped

Affirmation

Simple form	V-ing form
I must pipe you must pipe he must pipe we must pipe you must pipe they must pipe	I must be piping you must be piping he must be piping we must be piping you must be piping they must be piping
Perfect	V-ing perfect
I must have piped you must have piped he must have piped we must have piped you must have piped they must have piped	I must have been piping you must have been piping he must have been piping we must have been piping you must have been piping they must have been piping

Negation

Simple form	V-ing form
I must not pipe you must not pipe he must not pipe we must not pipe you must not pipe they must not pipe	I must not be piping you must not be piping he must not be piping we must not be piping you must not be piping they must not be piping
Perfect	V-ing perfect
I must not have piped you must not have piped he must not have piped we must not have piped you must not have piped they must not have piped	I must not have been piping you must not have been piping he must not have been piping we must not have been piping you must not have been piping they must not have been piping

Interrogative form

Simple form	V-ing form
must I pipe? must you pipe? must he pipe? must we pipe? must you pipe? must they pipe?	must I be piping? must you be piping? must he be piping? must we be piping? must you be piping? must they be piping?
Perfect	V-ing perfect
must I have piped? must you have piped? must he have piped? must we have piped? must you have piped? must they have piped?	must I have been piping? must you have been piping? must he have been piping? must we have been piping? must you have been piping? must they have been piping?

Interro-negative form

Simple form	V-ing form
must I not pipe? must you not pipe? must he not pipe? must we not pipe? must you not pipe? must they not pipe?	must I not be piping? must you not be piping? must he not be piping? must we not be piping? must you not be piping? must they not be piping?
Perfect	V-ing perfect
must I not have piped? must you not have piped? must he not have piped? must we not have piped? must you not have piped? must they not have piped?	must I not have been piping? must you not have been piping? must he not have been piping? must we not have been piping? must you not have been piping? must they not have been piping?