becase I need use some pics to explain my question, so I post the question to my googlepage.
http://wanghui1225.googlepages.com/xi_question_1http://wanghui1225.googlepages.com/xi_question_1">http://wanghui1225.googlepages.com/xi_question_1>
Regards,
Hui
Message was edited by: Wang Hui