•Postage stamps were introduced in Britain in 1840 as a way of showing that the sender had paid for the letter to be delivered.1840年，英国开始使用邮票，以表明寄信人已付邮资。

•The letter came back with ' return to sender - not known at this address' written on it.信被退了回来，上面写著「退还寄信人——此地址查无此人。”