could occur
Verbo regular: occur - occurred- occurred

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could occur
you could occur
she could occur
we could occur
you could occur
they could occur 	I could be occurring
you could be occurring
she could be occurring
we could be occurring
you could be occurring
they could be occurring	I could have occurred
you could have occurred
she could have occurred
we could have occurred
you could have occurred
they could have occurred	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	

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