Thank you,Kosmik.Thank you so much.
I think I can be helped by all the friends here,though my English is very poor.Use if don't try to use it, why I learn to speak English at first? If your sister don't have much time,or she think it is difficult to answer my question, I think she don't have to do that. I just want to konw the reason.
Thank you, you are so kind.