must giggle
Regular verb: giggle - giggled- giggled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must giggle
you must giggle
she must giggle
we must giggle
you must giggle
they must giggle 	I must be giggling
you must be giggling
she must be giggling
we must be giggling
you must be giggling
they must be giggling	I must have giggled
you must have giggled
she must have giggled
we must have giggled
you must have giggled
they must have giggled	I must have been giggling
you must have been giggling
she must have been giggling
we must have been giggling
you must have been giggling
they must have been giggling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't giggle
you mustn't giggle
she mustn't giggle
we mustn't giggle
you mustn't giggle
they mustn't giggle 	I mustn't be giggling
you mustn't be giggling
she mustn't be giggling
we mustn't be giggling
you mustn't be giggling
they mustn't be giggling	I mustn't have giggled
you mustn't have giggled
she mustn't have giggled
we mustn't have giggled
you mustn't have giggled
they mustn't have giggled	I mustn't have been giggling
you mustn't have been giggling
she mustn't have been giggling
we mustn't have been giggling
you mustn't have been giggling
they mustn't have been giggling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I giggle?
must you giggle?
must she giggle?
must we giggle?
must you giggle?
must they giggle? 	must I be giggling?
must you be giggling?
must she be giggling?
must we be giggling?
must you be giggling?
must they be giggling? 	must I have giggled?
must you have giggled?
must she have giggled?
must we have giggled?
must you have giggled?
must they have giggled? 	must I have been giggling?
must you have been giggling?
must she have been giggling?
must we have been giggling?
must you have been giggling?
must they have been giggling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I giggle?
mustn't you giggle?
mustn't she giggle?
mustn't we giggle?
mustn't you giggle?
mustn't they giggle? 	mustn't I be giggling?
mustn't you be giggling?
mustn't she be giggling?
mustn't we be giggling?
mustn't you be giggling?
mustn't they be giggling? 	mustn't I have giggled?
mustn't you have giggled?
mustn't she have giggled?
mustn't we have giggled?
mustn't you have giggled?
mustn't they have giggled? 	mustn't I have been giggling?
mustn't you have been giggling?
mustn't she have been giggling?
mustn't we have been giggling?
mustn't you have been giggling?
mustn't they have been giggling?