to fall / (computing) to go down (as when a computer or application becomes unresponsive) / (electrical engineering, of a circuit breaker) to trip / (informal) to fail an examination

as hard as one can; to the best of one's ability

(idiomatic) to keep a secret when asked about it, but let it slip inadvertently when chatting on another occasion

graduation examination

practical test

a mock exam

(law) a bar examination

oral examination; oral test

litmus test

everything