must shield
Regular verb: shield - shielded- shielded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must shield
you must shield
she must shield
we must shield
you must shield
they must shield 	I must be shielding
you must be shielding
she must be shielding
we must be shielding
you must be shielding
they must be shielding	I must have shielded
you must have shielded
she must have shielded
we must have shielded
you must have shielded
they must have shielded	I must have been shielding
you must have been shielding
she must have been shielding
we must have been shielding
you must have been shielding
they must have been shielding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't shield
you mustn't shield
she mustn't shield
we mustn't shield
you mustn't shield
they mustn't shield 	I mustn't be shielding
you mustn't be shielding
she mustn't be shielding
we mustn't be shielding
you mustn't be shielding
they mustn't be shielding	I mustn't have shielded
you mustn't have shielded
she mustn't have shielded
we mustn't have shielded
you mustn't have shielded
they mustn't have shielded	I mustn't have been shielding
you mustn't have been shielding
she mustn't have been shielding
we mustn't have been shielding
you mustn't have been shielding
they mustn't have been shielding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I shield?
must you shield?
must she shield?
must we shield?
must you shield?
must they shield? 	must I be shielding?
must you be shielding?
must she be shielding?
must we be shielding?
must you be shielding?
must they be shielding? 	must I have shielded?
must you have shielded?
must she have shielded?
must we have shielded?
must you have shielded?
must they have shielded? 	must I have been shielding?
must you have been shielding?
must she have been shielding?
must we have been shielding?
must you have been shielding?
must they have been shielding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I shield?
mustn't you shield?
mustn't she shield?
mustn't we shield?
mustn't you shield?
mustn't they shield? 	mustn't I be shielding?
mustn't you be shielding?
mustn't she be shielding?
mustn't we be shielding?
mustn't you be shielding?
mustn't they be shielding? 	mustn't I have shielded?
mustn't you have shielded?
mustn't she have shielded?
mustn't we have shielded?
mustn't you have shielded?
mustn't they have shielded? 	mustn't I have been shielding?
mustn't you have been shielding?
mustn't she have been shielding?
mustn't we have been shielding?
mustn't you have been shielding?
mustn't they have been shielding?