English verb conjugation
MUST INVESTIGATE

Regular verb: investigate - investigated - investigated

Affirmation

Simple form	V-ing form
I must investigate you must investigate he must investigate we must investigate you must investigate they must investigate	I must be investigating you must be investigating he must be investigating we must be investigating you must be investigating they must be investigating
Perfect	V-ing perfect
I must have investigated you must have investigated he must have investigated we must have investigated you must have investigated they must have investigated	I must have been investigating you must have been investigating he must have been investigating we must have been investigating you must have been investigating they must have been investigating

Negation

Simple form	V-ing form
I must not investigate you must not investigate he must not investigate we must not investigate you must not investigate they must not investigate	I must not be investigating you must not be investigating he must not be investigating we must not be investigating you must not be investigating they must not be investigating
Perfect	V-ing perfect
I must not have investigated you must not have investigated he must not have investigated we must not have investigated you must not have investigated they must not have investigated	I must not have been investigating you must not have been investigating he must not have been investigating we must not have been investigating you must not have been investigating they must not have been investigating

Interrogative form

Simple form	V-ing form
must I investigate? must you investigate? must he investigate? must we investigate? must you investigate? must they investigate?	must I be investigating? must you be investigating? must he be investigating? must we be investigating? must you be investigating? must they be investigating?
Perfect	V-ing perfect
must I have investigated? must you have investigated? must he have investigated? must we have investigated? must you have investigated? must they have investigated?	must I have been investigating? must you have been investigating? must he have been investigating? must we have been investigating? must you have been investigating? must they have been investigating?

Interro-negative form

Simple form	V-ing form
must I not investigate? must you not investigate? must he not investigate? must we not investigate? must you not investigate? must they not investigate?	must I not be investigating? must you not be investigating? must he not be investigating? must we not be investigating? must you not be investigating? must they not be investigating?
Perfect	V-ing perfect
must I not have investigated? must you not have investigated? must he not have investigated? must we not have investigated? must you not have investigated? must they not have investigated?	must I not have been investigating? must you not have been investigating? must he not have been investigating? must we not have been investigating? must you not have been investigating? must they not have been investigating?