open ticket与 open return ticket 的区别?

open ticket与 open return ticket 的区别? open ticket 与 ok ticket 的区别 open a ticket 请问：在英国买火车票,open 跟return ticket有什么区别? open ticket是什么类型的机票? 亚航有回程时间不固定的往返票票嘛?就是open return ticket~求各位大侠? return to,return from,return ticket区别 a ticket to 与a ticket for 的区别 ticket to 与ticket for造句 区别 price ticket 与price tickets的区别 How much is the ticket 与 How much for this ticket的区别 Fare 和ticket 的区别