could brief
Verbo regular: brief - briefed- briefed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could brief
you could brief
he could brief
we could brief
you could brief
they could brief 	I could be briefing
you could be briefing
he could be briefing
we could be briefing
you could be briefing
they could be briefing	I could have briefed
you could have briefed
he could have briefed
we could have briefed
you could have briefed
they could have briefed	I could have been briefing
you could have been briefing
he could have been briefing
we could have been briefing
you could have been briefing
they could have been briefing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not brief
you could not brief
he could not brief
we could not brief
you could not brief
they could not brief 	I could not be briefing
you could not be briefing
he could not be briefing
we could not be briefing
you could not be briefing
they could not be briefing	I could not have briefed
you could not have briefed
he could not have briefed
we could not have briefed
you could not have briefed
they could not have briefed	I could not have been briefing
you could not have been briefing
he could not have been briefing
we could not have been briefing
you could not have been briefing
they could not have been briefing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I brief?
could you brief?
could he brief?
could we brief?
could you brief?
could they brief? 	could I be briefing?
could you be briefing?
could he be briefing?
could we be briefing?
could you be briefing?
could they be briefing? 	could I have briefed?
could you have briefed?
could he have briefed?
could we have briefed?
could you have briefed?
could they have briefed? 	could I have been briefing?
could you have been briefing?
could he have been briefing?
could we have been briefing?
could you have been briefing?
could they have been briefing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not brief?
could you not brief?
could he not brief?
could we not brief?
could you not brief?
could they not brief? 	could I not be briefing?
could you not be briefing?
could he not be briefing?
could we not be briefing?
could you not be briefing?
could they not be briefing? 	could I not have briefed?
could you not have briefed?
could he not have briefed?
could we not have briefed?
could you not have briefed?
could they not have briefed? 	could I not have been briefing?
could you not have been briefing?
could he not have been briefing?
could we not have been briefing?
could you not have been briefing?
could they not have been briefing?