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