小岗的妈妈工作很忙,于是小岗去外地姥姥家上学。他每隔3天就给妈妈写一封信,可过了好久,还是接不到妈妈的回信。小岗正着急时,妈妈终于来信了。信上说,不知道你过得好不好,妈妈一直惦记着你,门口信箱里有几封信,不知道是不是你寄来的。你把信箱钥匙带走了,我无法取信,请把钥匙 Xiaogang's mother busy work, so Xiaogang to the grandma home to school. He wrote a letter to his mother every 3 days, but after a long time, he still could not get a reply from his mother. Small hill is anxious, my mother finally letter. The letter said, I do not know if you have a good time, my mother always remember you, there are several letters in the mailbox, do not know if you sent it. You took the mailbox key, I can not get the letter, please the key