I see no principle; it is more a matter of practice. Some will take one or not, or both ways. I find these all natural-sounding, though local practice may use only one form: Tomb-sweeping Day///the Tomb-sweeping Day Lantern Festival///the Lantern Festival the Mid-Autumn Festival/// Mid-Autumn Festival the Double Ninth Festival/// Double Ninth Festival the Cherry Blossom Festival///Cherry Blossom Festival Songkran Festival Day///the Songkran Festival Day Corban-- I don't know what this word means, so I don't know whether an article is reasonable.
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