I could occur you could occur she could occur we could occur you could occur they could occur
Forma con V-ing
I could be occurring you could be occurring she could be occurring we could be occurring you could be occurring they could be occurring
Perfecto
I could have occurred you could have occurred she could have occurred we could have occurred you could have occurred they could have occurred
Perfecto con V-ing
I could have been occurring you could have been occurring she could have been occurring we could have been occurring you could have been occurring they could have been occurring
Negación
Forma simple
I could not occur you could not occur she could not occur we could not occur you could not occur they could not occur
Forma con V-ing
I could not be occurring you could not be occurring she could not be occurring we could not be occurring you could not be occurring they could not be occurring
Perfecto
I could not have occurred you could not have occurred she could not have occurred we could not have occurred you could not have occurred they could not have occurred
Perfecto con V-ing
I could not have been occurring you could not have been occurring she 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 she occur? could we occur? could you occur? could they occur?
Forma con V-ing
could I be occurring? could you be occurring? could she be occurring? could we be occurring? could you be occurring? could they be occurring?
Perfecto
could I have occurred? could you have occurred? could she have occurred? could we have occurred? could you have occurred? could they have occurred?
Perfecto con V-ing
could I have been occurring? could you have been occurring? could she have been occurring? could we have been occurring? could you have been occurring? could they have been occurring?
Forma interro-negativa
Forma simple
could I not occur? could you not occur? could she not occur? could we not occur? could you not occur? could they not occur?
Forma con V-ing
could I not be occurring? could you not be occurring? could she not be occurring? could we not be occurring? could you not be occurring? could they not be occurring?
Perfecto
could I not have occurred? could you not have occurred? could she not have occurred? could we not have occurred? could you not have occurred? could they not have occurred?
Perfecto con V-ing
could I not have been occurring? could you not have been occurring? could she not have been occurring? could we not have been occurring? could you not have been occurring? could they not have been occurring?