Collocations for occur - verb

commonly, frequently, often, regularly, repeatedly
generally, normally, typically, usually
infrequently, rarely
occasionally, sometimes
randomly, sporadically
mainly, mostly, predominantly, primarily
exclusively, only
naturally
These chemical changes occur naturally.

spontaneously
Opportunities for learning occur spontaneously every day.

simultaneously, together
independently
quickly, rapidly
slowly

be likely to, tend to
be unlikely to

among
the problems that occur among people living together

in
A significant improvement occurred in patients given the drug.

Occur is used with these nouns as the subject:
abuse, accident, adaptation, ambiguity, assault, atrocity, attack, bias, blast, breakdown, cancer, case, catastrophe, change, clash, collision, complication, compound, conflict, consequence, conversation, crash, crime, crisis, damage, death, debate, decline, delay, depression, deterioration, development, difference, dilemma, disagreement, disaster, discrepancy, discrimination, disease, dispute, disruption, disturbance, earthquake, effect, emergency, encounter, epidemic, erosion, error, eruption, event, evolution, expansion, explosion, failure, fall, fault, fire, fit, fluctuation, illness, imbalance, impact, improvement, incident, increase, infection, injury, innovation, instability, instance, intercourse, irregularity, killing, leak, meeting, migration, mineral, miracle, mistake, misunderstanding, moment, movement, murder, mutation, opportunity, outage, outbreak, pain, phenomenon, problem, process, reaction, rebellion, recovery, reduction, relapse, reproduction, revolution, rift, riot, scene, shift, shortage, situation, skirmish, species, split, strike, subsidence, swelling, symptom, syndrome, thing, tide, tragedy, transfer, transformation, transition, vacancy, variation, violence