must ski
Verbo regular: ski - skied- skied

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must ski
you must ski
he must ski
we must ski
you must ski
they must ski 	I must be skiing
you must be skiing
he must be skiing
we must be skiing
you must be skiing
they must be skiing	I must have skied
you must have skied
he must have skied
we must have skied
you must have skied
they must have skied	I must have been skiing
you must have been skiing
he must have been skiing
we must have been skiing
you must have been skiing
they must have been skiing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must not ski
you must not ski
he must not ski
we must not ski
you must not ski
they must not ski 	I must not be skiing
you must not be skiing
he must not be skiing
we must not be skiing
you must not be skiing
they must not be skiing	I must not have skied
you must not have skied
he must not have skied
we must not have skied
you must not have skied
they must not have skied	I must not have been skiing
you must not have been skiing
he must not have been skiing
we must not have been skiing
you must not have been skiing
they must not have been skiing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I ski?
must you ski?
must he ski?
must we ski?
must you ski?
must they ski? 	must I be skiing?
must you be skiing?
must he be skiing?
must we be skiing?
must you be skiing?
must they be skiing? 	must I have skied?
must you have skied?
must he have skied?
must we have skied?
must you have skied?
must they have skied? 	must I have been skiing?
must you have been skiing?
must he have been skiing?
must we have been skiing?
must you have been skiing?
must they have been skiing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I not ski?
must you not ski?
must he not ski?
must we not ski?
must you not ski?
must they not ski? 	must I not be skiing?
must you not be skiing?
must he not be skiing?
must we not be skiing?
must you not be skiing?
must they not be skiing? 	must I not have skied?
must you not have skied?
must he not have skied?
must we not have skied?
must you not have skied?
must they not have skied? 	must I not have been skiing?
must you not have been skiing?
must he not have been skiing?
must we not have been skiing?
must you not have been skiing?
must they not have been skiing?