PS There is no minimum or maximum length for the personal statement. Brevity is preferred. The statement serves as both a writing sample and opportunity for you to explain, why you are applying, what makes you a good fit, and anything that may be unclear elsewhere on your application. CV Resumé or Curriculum Vitae Fee $85 non-refundable application fee RL Three recommendation letters. For PhD applicants, it is usually best to ask professors from your current or most recent academic institution. Research supervisors are strongly preferred over classroom teachers, unless the course(s) involved a substantial project. （详情见http://gradengineering.columbia.edu/application-materials） Transcript The transcript copy you upload onto your online application must be an official copy, which is typically obtained from your college or university Registrar's office or the office that issues official transcripts to students. Uploading anything other than a copy of your official transcript may cause delay in the review of your application.