Example sentences

1. 手紙を出す前に切手を貼るのを忘れた。

   I forgot to put on the stamp before I mailed the letter.

2. 手紙に切手を貼るのを忘れるな。

   Don't forget to put a stamp on your letter.

3. 私が出して欲しいと頼んだ手紙に切手を貼るのを忘れないでね。

   Please don't forget to put stamps on the letters I gave you to post.