triennially

adv: The games occur triennially. 运动会每三年举行一次.

tribesman, tribulation, tribunal, tributary, tribute, trice, triceps, trick, trickery, trickily, trickiness, trickle, trickle charger, trickster, tricky, tricolour (US tricolor), tricycle, trident, tried, triennial, trier, trifle, trifler, trifling, trigger, trigger-happy, triglyceride, trigonometric, trigonometrical, trigonometrically, trigonometry, trike, trilateral, trilaterally, trilby, trilingual, trill, trillion, trillionth, trilobite, trilogy,