1、Tom climbed into in the letter box and shut the door from the inside.
湯姆爬進(jìn)了信箱里，然后從里面將門關(guān)上。

2、the number of a letter box at the post office where mail is collected.
郵局用來(lái)收集信件的信箱的號(hào)碼。

3、That afternoon she dropped it into the letter box at the post office.
下午的時(shí)候她把信放進(jìn)了郵局的郵箱。