古代中国封建社会出现“有力者无田可耕，有田者无力可耕”现象的根本原因是（    ）

假设你是Mei Ling，是光明中学七年级学生，想与Xiao Xin结为朋友。请阅读Xiao Xin的e-mail，并根据下面思维导图提供的信息，给Xiao Xin回封电子邮件。

Hi dear,

    My name is Xiao Xin. I'm thirteen. I'm a student from Wuhan NO.1 Middle School. I like P.E. because our school has a nice and good playground(运动场). I can play soccer there. Also, I like science, it's very interesting. So it is my favorite subject. Oh, November 20th is my birthday. What ab out yours? Let's be friends. Is that OK with you?

    Best wishes!

XiaoXin

    要求：（1）回信中必须包含思维导图中所提供的内容，并就相关内容可适当发挥但不要出现真实的个人信息(人名、地名、学校名等)；（2）词数60左右(开头句已给出，不计入总词数)。

    Hi Xiao Xin,

    Thank you for your e-mail. ……

    See you soon.

Mei Ling