航运订票系统：若剩余票数足够, 则可以进行直接订票, 若不够可进行，候补订票, 当有人退票时, 就从候补名单中选取合适者进行订票。 -shipping booking system : If the remaining votes enough, they can direct booking, if not available, alternate booking, When someone Refund, from the list of alternates were selected s