Too many circumstances occur on the spot to modify them.

Well, for once it may pass; but please not to let the circumstance occur too often.

Erm and the question of course is, you know, how often do these circumstances occur?

He was almost to the garage when the circumstance occurred.

Ordinarily, those circumstances do not occur in the life of the average person.

We do not have, in just an effect, such an answer to the question of why a causal circumstance occurred.

Such a circumstance had never before occurred, and the real cause of their departure is still a mystery.

In the evening a few circumstances occurred which he thought more promising.

Then a very surprising circumstance occurred, which I shall tell you in due course.

By the early 13th century, similar circumstances were occurring in Spain.