He said the letter might have been returned to the sender.
他说，信可能已退还寄信人了。
The post office generally will send the dead letters back to the senders.
邮局一般会将挂号的瞎信退给寄信人。
The return address was a law firm in Seattle.
寄信人地址是西雅图一家律师事务所。
If undelivered, please return to sender.
如果无法送达，请退回寄信人。
The envelope was worn and the only thing that was legible on it was the return address.
信封已磨损，惟有寄信人的住址还清晰可辨。
And offer to send letters to people who are not collecting stamps.
主动给那些不集邮的人寄寄信。
having the postage paid by the sender.
由发信人付款的邮寄。
write and send a letter(to sb)
（给某人） 写信并寄出
Are postcards cheaper to send than a letter ?
寄明信片比寄信便宜吗？
The letter be addressed to the occupier of the house
这封信是寄给房子的居住人的
The letter is addressed to the occupier of the house.
这封信是寄给房子的居住人的。
The letter was addressed to the occupier of the house.
这封信是寄给房子的居住人的.
expresses hope that something will be successful.
对某事的成功寄以希望和信心的人。
Dashan: Have you sent any postcards home yet?
大山：你给家里人寄过明信片了吗？
Forward to
将（信件、包裹）寄给（某人某地）
She wrote often, and this was noticed.
她时常寄信,这就引起旁人的注意。
moderated mailing-list
ph.1. 【电脑】信件区管理人邮寄目录
He used what ink there was left after drafting his circular to write a letter to his wife.
于是蘸着刚才的残墨写寄与夫人的信。