English verb conjugation
CAN OCCUR

Regular verb: occur - occurred - occurred

Affirmation

Simple form	V-ing form
I can occur you can occur she can occur we can occur you can occur they can occur	I can be occurring you can be occurring she can be occurring we can be occurring you can be occurring they can be occurring
Perfect	V-ing perfect
I can have occurred you can have occurred she can have occurred we can have occurred you can have occurred they can have occurred	I can have been occurring you can have been occurring she can have been occurring we can have been occurring you can have been occurring they can have been occurring

Negation

Simple form	V-ing form
I cannot occur you cannot occur she cannot occur we cannot occur you cannot occur they cannot occur	I cannot be occurring you cannot be occurring she cannot be occurring we cannot be occurring you cannot be occurring they cannot be occurring
Perfect	V-ing perfect
I cannot have occurred you cannot have occurred she cannot have occurred we cannot have occurred you cannot have occurred they cannot have occurred	I cannot have been occurring you cannot have been occurring she cannot have been occurring we cannot have been occurring you cannot have been occurring they cannot have been occurring

Interrogative form

Simple form	V-ing form
can I occur? can you occur? can she occur? can we occur? can you occur? can they occur?	can I be occurring? can you be occurring? can she be occurring? can we be occurring? can you be occurring? can they be occurring?
Perfect	V-ing perfect
can I have occurred? can you have occurred? can she have occurred? can we have occurred? can you have occurred? can they have occurred?	can I have been occurring? can you have been occurring? can she have been occurring? can we have been occurring? can you have been occurring? can they have been occurring?

Interro-negative form

Simple form	V-ing form
can I not occur? can you not occur? can she not occur? can we not occur? can you not occur? can they not occur?	can I not be occurring? can you not be occurring? can she not be occurring? can we not be occurring? can you not be occurring? can they not be occurring?
Perfect	V-ing perfect
can I not have occurred? can you not have occurred? can she not have occurred? can we not have occurred? can you not have occurred? can they not have occurred?	can I not have been occurring? can you not have been occurring? can she not have been occurring? can we not have been occurring? can you not have been occurring? can they not have been occurring?