must succumb
Verbo regular: succumb - succumbed- succumbed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must succumb
you must succumb
he must succumb
we must succumb
you must succumb
they must succumb 	I must be succumbing
you must be succumbing
he must be succumbing
we must be succumbing
you must be succumbing
they must be succumbing	I must have succumbed
you must have succumbed
he must have succumbed
we must have succumbed
you must have succumbed
they must have succumbed	I must have been succumbing
you must have been succumbing
he must have been succumbing
we must have been succumbing
you must have been succumbing
they must have been succumbing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not succumb
you must not succumb
he must not succumb
we must not succumb
you must not succumb
they must not succumb 	I must not be succumbing
you must not be succumbing
he must not be succumbing
we must not be succumbing
you must not be succumbing
they must not be succumbing	I must not have succumbed
you must not have succumbed
he must not have succumbed
we must not have succumbed
you must not have succumbed
they must not have succumbed	I must not have been succumbing
you must not have been succumbing
he must not have been succumbing
we must not have been succumbing
you must not have been succumbing
they must not have been succumbing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I succumb?
must you succumb?
must he succumb?
must we succumb?
must you succumb?
must they succumb? 	must I be succumbing?
must you be succumbing?
must he be succumbing?
must we be succumbing?
must you be succumbing?
must they be succumbing? 	must I have succumbed?
must you have succumbed?
must he have succumbed?
must we have succumbed?
must you have succumbed?
must they have succumbed? 	must I have been succumbing?
must you have been succumbing?
must he have been succumbing?
must we have been succumbing?
must you have been succumbing?
must they have been succumbing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not succumb?
must you not succumb?
must he not succumb?
must we not succumb?
must you not succumb?
must they not succumb? 	must I not be succumbing?
must you not be succumbing?
must he not be succumbing?
must we not be succumbing?
must you not be succumbing?
must they not be succumbing? 	must I not have succumbed?
must you not have succumbed?
must he not have succumbed?
must we not have succumbed?
must you not have succumbed?
must they not have succumbed? 	must I not have been succumbing?
must you not have been succumbing?
must he not have been succumbing?
must we not have been succumbing?
must you not have been succumbing?
must they not have been succumbing?