信封是人们用来装信件的纸袋Envelope is a paper pocket, which people put their letter in it 首先我们要写一封信 然后把它装到信封里 最后把它放进邮筒邮递出去First I am going to write a letter, and then put it in an envelope, finally, put it in the post box and send it away. 很乐意能够帮到你,希望会对你有助。若不明白请继续问,如满意敬请采纳,O(∩_∩)O谢谢你。