Hello 玉兎,
Thank you for your post.
However, unfortunately, I'm afraid it might be difficult for you to get a reply since people usually use Japanese here.
And your post is the question about a license, not about a technical problem.
So it might not be the appropriate place to ask the question.
You could see
Microsoft® SQL Server® 2008 R2 End User License Agreements
http://www.microsoft.com/download/en/details.aspx?id=2803
Microsoft SQL Server 2008 R2 RTM - Express
http://www.microsoft.com/download/en/details.aspx?id=3743#overview
You could also call contact Microsoft Customer Support Services (CSS) directly via
http://support.microsoft.com/default.aspx?scid=fh;EN-US;PHONENUMBERS
I hope these help you.
Thanks,
Harumi Yamamamoto - Moderator (MSKK)