Dear Mr Smith：
I am the organizer of an engligh speech contest In our school 。
It is a great pleasure for me to have a wonderful choice to put pen to paper and invite you to be a judge.
I will tell you details about the contest。
To begin with，the time of contest is at next weekend。
Secondly，It will happen in Our school。thirdly，the topic is “should students learn law”。
as a result，10 students will do an engilsh speech。
thank you for your consideration，and i am looking forward to your reply and agree。
