经典句型:I want to buy a ticket to Shanghai. 我要买一张到上海的票。

A:I want to buy a ticket to Shanghai.
甲:我要买一张到上海的票。
B:Do you want a sleeper?
乙:要卧铺吗?
A:How much does a sleeper cost?
甲:卧铺多少钱?
A:The lower berth costs 285 yuan,the middle 279 yuan and the upper berth costs 273 yuan.
甲:下铺285元，中铺279元，上铺273元。
B:I'd like a lower one.
乙:我要一张下铺。

经典句型:I'd like an upper berth. 我要上铺。

A:Do you have a lower one?
甲:有下铺吗？
B:No,there're only middle ones and upper ones left.
乙:没有了，只剩中铺和上铺了。
A:I'd like an upper one.
甲:我要一张上铺。

句型讲解：
火车上的sleeper是“卧铺”的意思，也可以用berth来表示。上中下铺分别是upper berth,middle berth和lower berth。