English verb conjugation
CAN OCCUR

Regular verb: occur - occurred - occurred

Affirmation

Simple form	V-ing form
I can occur you can occur he can occur we can occur you can occur they can occur	I can be occurring you can be occurring he 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 he 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 he 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 can't occur you can't occur he can't occur we can't occur you can't occur they can't occur	I can't be occurring you can't be occurring he can't be occurring we can't be occurring you can't be occurring they can't be occurring
Perfect	V-ing perfect
I can't have occurred you can't have occurred he can't have occurred we can't have occurred you can't have occurred they can't have occurred	I can't have been occurring you can't have been occurring he can't have been occurring we can't have been occurring you can't have been occurring they can't have been occurring

Interrogative form

Simple form	V-ing form
can I occur? can you occur? can he occur? can we occur? can you occur? can they occur?	can I be occurring? can you be occurring? can he 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 he 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 he 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't I occur? can't you occur? can't he occur? can't we occur? can't you occur? can't they occur?	can't I be occurring? can't you be occurring? can't he be occurring? can't we be occurring? can't you be occurring? can't they be occurring?
Perfect	V-ing perfect
can't I have occurred? can't you have occurred? can't he have occurred? can't we have occurred? can't you have occurred? can't they have occurred?	can't I have been occurring? can't you have been occurring? can't he have been occurring? can't we have been occurring? can't you have been occurring? can't they have been occurring?