must endeavour
Regular verb: endeavour - endeavoured- endeavoured

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must endeavour
you must endeavour
she must endeavour
we must endeavour
you must endeavour
they must endeavour 	I must be endeavouring
you must be endeavouring
she must be endeavouring
we must be endeavouring
you must be endeavouring
they must be endeavouring	I must have endeavoured
you must have endeavoured
she must have endeavoured
we must have endeavoured
you must have endeavoured
they must have endeavoured	I must have been endeavouring
you must have been endeavouring
she must have been endeavouring
we must have been endeavouring
you must have been endeavouring
they must have been endeavouring	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't endeavour
you mustn't endeavour
she mustn't endeavour
we mustn't endeavour
you mustn't endeavour
they mustn't endeavour 	I mustn't be endeavouring
you mustn't be endeavouring
she mustn't be endeavouring
we mustn't be endeavouring
you mustn't be endeavouring
they mustn't be endeavouring	I mustn't have endeavoured
you mustn't have endeavoured
she mustn't have endeavoured
we mustn't have endeavoured
you mustn't have endeavoured
they mustn't have endeavoured	I mustn't have been endeavouring
you mustn't have been endeavouring
she mustn't have been endeavouring
we mustn't have been endeavouring
you mustn't have been endeavouring
they mustn't have been endeavouring	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I endeavour?
must you endeavour?
must she endeavour?
must we endeavour?
must you endeavour?
must they endeavour? 	must I be endeavouring?
must you be endeavouring?
must she be endeavouring?
must we be endeavouring?
must you be endeavouring?
must they be endeavouring? 	must I have endeavoured?
must you have endeavoured?
must she have endeavoured?
must we have endeavoured?
must you have endeavoured?
must they have endeavoured? 	must I have been endeavouring?
must you have been endeavouring?
must she have been endeavouring?
must we have been endeavouring?
must you have been endeavouring?
must they have been endeavouring? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I endeavour?
mustn't you endeavour?
mustn't she endeavour?
mustn't we endeavour?
mustn't you endeavour?
mustn't they endeavour? 	mustn't I be endeavouring?
mustn't you be endeavouring?
mustn't she be endeavouring?
mustn't we be endeavouring?
mustn't you be endeavouring?
mustn't they be endeavouring? 	mustn't I have endeavoured?
mustn't you have endeavoured?
mustn't she have endeavoured?
mustn't we have endeavoured?
mustn't you have endeavoured?
mustn't they have endeavoured? 	mustn't I have been endeavouring?
mustn't you have been endeavouring?
mustn't she have been endeavouring?
mustn't we have been endeavouring?
mustn't you have been endeavouring?
mustn't they have been endeavouring?