信的单词怎么写

letter:a written or printed message that is usually put in an envelope and sent by mail 信，信件

letter是作“信，信件”是可数名词，通常与动词post,mail,read,receive,send,,write搭配，也就是说

写信write a letter

寄信post/mail/send a letter

收到信receive/get a letter

阅读信read a letter