must backfire
Verbo regular: backfire - backfired- backfired

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must backfire
you must backfire
she must backfire
we must backfire
you must backfire
they must backfire 	I must be backfiring
you must be backfiring
she must be backfiring
we must be backfiring
you must be backfiring
they must be backfiring	I must have backfired
you must have backfired
she must have backfired
we must have backfired
you must have backfired
they must have backfired	I must have been backfiring
you must have been backfiring
she must have been backfiring
we must have been backfiring
you must have been backfiring
they must have been backfiring	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not backfire
you must not backfire
she must not backfire
we must not backfire
you must not backfire
they must not backfire 	I must not be backfiring
you must not be backfiring
she must not be backfiring
we must not be backfiring
you must not be backfiring
they must not be backfiring	I must not have backfired
you must not have backfired
she must not have backfired
we must not have backfired
you must not have backfired
they must not have backfired	I must not have been backfiring
you must not have been backfiring
she must not have been backfiring
we must not have been backfiring
you must not have been backfiring
they must not have been backfiring	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I backfire?
must you backfire?
must she backfire?
must we backfire?
must you backfire?
must they backfire? 	must I be backfiring?
must you be backfiring?
must she be backfiring?
must we be backfiring?
must you be backfiring?
must they be backfiring? 	must I have backfired?
must you have backfired?
must she have backfired?
must we have backfired?
must you have backfired?
must they have backfired? 	must I have been backfiring?
must you have been backfiring?
must she have been backfiring?
must we have been backfiring?
must you have been backfiring?
must they have been backfiring? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not backfire?
must you not backfire?
must she not backfire?
must we not backfire?
must you not backfire?
must they not backfire? 	must I not be backfiring?
must you not be backfiring?
must she not be backfiring?
must we not be backfiring?
must you not be backfiring?
must they not be backfiring? 	must I not have backfired?
must you not have backfired?
must she not have backfired?
must we not have backfired?
must you not have backfired?
must they not have backfired? 	must I not have been backfiring?
must you not have been backfiring?
must she not have been backfiring?
must we not have been backfiring?
must you not have been backfiring?
must they not have been backfiring?