English verb conjugation
MUST PIGGYBACK

Regular verb: piggyback - piggybacked - piggybacked

Affirmation

Simple form	V-ing form
I must piggyback you must piggyback he must piggyback we must piggyback you must piggyback they must piggyback	I must be piggybacking you must be piggybacking he must be piggybacking we must be piggybacking you must be piggybacking they must be piggybacking
Perfect	V-ing perfect
I must have piggybacked you must have piggybacked he must have piggybacked we must have piggybacked you must have piggybacked they must have piggybacked	I must have been piggybacking you must have been piggybacking he must have been piggybacking we must have been piggybacking you must have been piggybacking they must have been piggybacking

Negation

Simple form	V-ing form
I must not piggyback you must not piggyback he must not piggyback we must not piggyback you must not piggyback they must not piggyback	I must not be piggybacking you must not be piggybacking he must not be piggybacking we must not be piggybacking you must not be piggybacking they must not be piggybacking
Perfect	V-ing perfect
I must not have piggybacked you must not have piggybacked he must not have piggybacked we must not have piggybacked you must not have piggybacked they must not have piggybacked	I must not have been piggybacking you must not have been piggybacking he must not have been piggybacking we must not have been piggybacking you must not have been piggybacking they must not have been piggybacking

Interrogative form

Simple form	V-ing form
must I piggyback? must you piggyback? must he piggyback? must we piggyback? must you piggyback? must they piggyback?	must I be piggybacking? must you be piggybacking? must he be piggybacking? must we be piggybacking? must you be piggybacking? must they be piggybacking?
Perfect	V-ing perfect
must I have piggybacked? must you have piggybacked? must he have piggybacked? must we have piggybacked? must you have piggybacked? must they have piggybacked?	must I have been piggybacking? must you have been piggybacking? must he have been piggybacking? must we have been piggybacking? must you have been piggybacking? must they have been piggybacking?

Interro-negative form

Simple form	V-ing form
must I not piggyback? must you not piggyback? must he not piggyback? must we not piggyback? must you not piggyback? must they not piggyback?	must I not be piggybacking? must you not be piggybacking? must he not be piggybacking? must we not be piggybacking? must you not be piggybacking? must they not be piggybacking?
Perfect	V-ing perfect
must I not have piggybacked? must you not have piggybacked? must he not have piggybacked? must we not have piggybacked? must you not have piggybacked? must they not have piggybacked?	must I not have been piggybacking? must you not have been piggybacking? must he not have been piggybacking? must we not have been piggybacking? must you not have been piggybacking? must they not have been piggybacking?