例句：

　　1、Why write a letter to your future self?

　　為什么要給未來的自己寫一封信呢？

　　2、Perhaps they are afraid the imaginary letter will come true.

　　也許他們害怕那封虛構的信會成為現實。

　　3、 An important letter served the lawyer as evidence.

　　一封重要的信件被律師作為證據。