有关texas tech univ 要求的sop的疑问。。。。。。。。

收到他家的邮件，说是做个调查，问我为什么选择读研之类，然后要求写sop。信的内容如下：
From your responses on this questionnaire, you stated that you are interested in attending TTU as an on-campus student as opposed to a distance student. Further documentation is needed in order for us to process your application, a Statement of Purpose (SOP). This SOP should be approximately 1 to 1.5 pages in length and should include why you are interested in the interdisciplinary aspects of the Master of Engineering degree as opposed to a more structured Master of Science (MS) degree. It should also answer the following questions:

1)        Why is MEN the best choice?
2)        What three or more areas do you intend to pursue in the MEN program?
3)        In what ways will gaining knowledge in the subject areas (selected above) benefit you professionally?
4)        How will the accumulation of these courses provide a cohesive focus for this master’s degree?

请问我可以发个以前自己写好的ps过去行吗？还有，我ps都提交了，这个sop重要吗？

问一下，ttu的ee的ps 推荐信要送到ece吗？