must discover
Regular verb: discover - discovered- discovered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must discover
you must discover
she must discover
we must discover
you must discover
they must discover 	I must be discovering
you must be discovering
she must be discovering
we must be discovering
you must be discovering
they must be discovering	I must have discovered
you must have discovered
she must have discovered
we must have discovered
you must have discovered
they must have discovered	I must have been discovering
you must have been discovering
she must have been discovering
we must have been discovering
you must have been discovering
they must have been discovering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't discover
you mustn't discover
she mustn't discover
we mustn't discover
you mustn't discover
they mustn't discover 	I mustn't be discovering
you mustn't be discovering
she mustn't be discovering
we mustn't be discovering
you mustn't be discovering
they mustn't be discovering	I mustn't have discovered
you mustn't have discovered
she mustn't have discovered
we mustn't have discovered
you mustn't have discovered
they mustn't have discovered	I mustn't have been discovering
you mustn't have been discovering
she mustn't have been discovering
we mustn't have been discovering
you mustn't have been discovering
they mustn't have been discovering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I discover?
must you discover?
must she discover?
must we discover?
must you discover?
must they discover? 	must I be discovering?
must you be discovering?
must she be discovering?
must we be discovering?
must you be discovering?
must they be discovering? 	must I have discovered?
must you have discovered?
must she have discovered?
must we have discovered?
must you have discovered?
must they have discovered? 	must I have been discovering?
must you have been discovering?
must she have been discovering?
must we have been discovering?
must you have been discovering?
must they have been discovering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I discover?
mustn't you discover?
mustn't she discover?
mustn't we discover?
mustn't you discover?
mustn't they discover? 	mustn't I be discovering?
mustn't you be discovering?
mustn't she be discovering?
mustn't we be discovering?
mustn't you be discovering?
mustn't they be discovering? 	mustn't I have discovered?
mustn't you have discovered?
mustn't she have discovered?
mustn't we have discovered?
mustn't you have discovered?
mustn't they have discovered? 	mustn't I have been discovering?
mustn't you have been discovering?
mustn't she have been discovering?
mustn't we have been discovering?
mustn't you have been discovering?
mustn't they have been discovering?