must quail
Regular verb: quail - quailed- quailed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must quail
you must quail
she must quail
we must quail
you must quail
they must quail 	I must be quailing
you must be quailing
she must be quailing
we must be quailing
you must be quailing
they must be quailing	I must have quailed
you must have quailed
she must have quailed
we must have quailed
you must have quailed
they must have quailed	I must have been quailing
you must have been quailing
she must have been quailing
we must have been quailing
you must have been quailing
they must have been quailing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't quail
you mustn't quail
she mustn't quail
we mustn't quail
you mustn't quail
they mustn't quail 	I mustn't be quailing
you mustn't be quailing
she mustn't be quailing
we mustn't be quailing
you mustn't be quailing
they mustn't be quailing	I mustn't have quailed
you mustn't have quailed
she mustn't have quailed
we mustn't have quailed
you mustn't have quailed
they mustn't have quailed	I mustn't have been quailing
you mustn't have been quailing
she mustn't have been quailing
we mustn't have been quailing
you mustn't have been quailing
they mustn't have been quailing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I quail?
must you quail?
must she quail?
must we quail?
must you quail?
must they quail? 	must I be quailing?
must you be quailing?
must she be quailing?
must we be quailing?
must you be quailing?
must they be quailing? 	must I have quailed?
must you have quailed?
must she have quailed?
must we have quailed?
must you have quailed?
must they have quailed? 	must I have been quailing?
must you have been quailing?
must she have been quailing?
must we have been quailing?
must you have been quailing?
must they have been quailing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I quail?
mustn't you quail?
mustn't she quail?
mustn't we quail?
mustn't you quail?
mustn't they quail? 	mustn't I be quailing?
mustn't you be quailing?
mustn't she be quailing?
mustn't we be quailing?
mustn't you be quailing?
mustn't they be quailing? 	mustn't I have quailed?
mustn't you have quailed?
mustn't she have quailed?
mustn't we have quailed?
mustn't you have quailed?
mustn't they have quailed? 	mustn't I have been quailing?
mustn't you have been quailing?
mustn't she have been quailing?
mustn't we have been quailing?
mustn't you have been quailing?
mustn't they have been quailing?