The phrase "a rule occurs" is correct and usable in written English.
It can be used in contexts discussing the emergence or application of a rule in a specific situation or system.
Example: "In this game, a rule occurs when a player violates the established guidelines."
Alternatives: "a rule is established" or "a rule takes effect".
Conjectures as a rule occur to the mind spontaneously or not at all; diagnosis and prescription often present themselves at the same moment.
One exception to this rule occurs when a baserunner attempts to steal a base.
In the specific situation of Wisconsin Card Sorting Test (Cunha et al., 2005), the inflexibility may take place when a change in the sorting rule occurs and the subject perseveres in the previous rule because a new plan was not formed or was formed but was not executed.
A commonly misunderstood use of the offside rule occurs when the keeper leaves his line on a set piece and there is only one defender on the line.
The support of a prescribed drug set X was defined as the proportion of all prescriptions in the data set that contained the drug set X. Support is a measure of how frequently the rule occurs in the database.
The only exception to the rule occurs when investors think that monetary policy has a drastically wrong bias.
An exception to this rule occurs when one resistance mechanism, such as an efflux pump, confers resistance to many types of drugs simultaneously.
An exception to this rule occurs in species that can disconnect body parts—some lizards and salamanders are able to detach their tails if they are attacked by a predator.
The exception to this rule occurs when the mixed bed is punished for being hot as either the equilibrium ceiling on the primary reaction drops sharply or a competitive reaction dominates at high temperature.
An exception to this rule occurs during medal presentation ceremonies at multi-sport events such as the Olympics and Asian Games.
