I could occur you could occur he could occur we could occur you could occur they could occur
Forma com V-ing
I could be occurring you could be occurring he could be occurring we could be occurring you could be occurring they could be occurring
Perfeito
I could have occurred you could have occurred he could have occurred we could have occurred you could have occurred they could have occurred
Perfeito com V-ing
I could have been occurring you could have been occurring he could have been occurring we could have been occurring you could have been occurring they could have been occurring
Negação
Forma simple
I could not occur you could not occur he could not occur we could not occur you could not occur they could not occur
Forma com V-ing
I could not be occurring you could not be occurring he could not be occurring we could not be occurring you could not be occurring they could not be occurring
Perfeito
I could not have occurred you could not have occurred he could not have occurred we could not have occurred you could not have occurred they could not have occurred
Perfeito com V-ing
I could not have been occurring you could not have been occurring he could not have been occurring we could not have been occurring you could not have been occurring they could not have been occurring
Forma interrogativa
Forma simple
could I occur? could you occur? could he occur? could we occur? could you occur? could they occur?
Forma com V-ing
could I be occurring? could you be occurring? could he be occurring? could we be occurring? could you be occurring? could they be occurring?
Perfeito
could I have occurred? could you have occurred? could he have occurred? could we have occurred? could you have occurred? could they have occurred?
Perfeito com V-ing
could I have been occurring? could you have been occurring? could he have been occurring? could we have been occurring? could you have been occurring? could they have been occurring?
Forma interro-Negação
Forma simple
could I not occur? could you not occur? could he not occur? could we not occur? could you not occur? could they not occur?
Forma com V-ing
could I not be occurring? could you not be occurring? could he not be occurring? could we not be occurring? could you not be occurring? could they not be occurring?
Perfeito
could I not have occurred? could you not have occurred? could he not have occurred? could we not have occurred? could you not have occurred? could they not have occurred?
Perfeito com V-ing
could I not have been occurring? could you not have been occurring? could he not have been occurring? could we not have been occurring? could you not have been occurring? could they not have been occurring?