美国签证如何续签？
以下是我当时续签用的材料清单，仅供参考. 1) I-20 (original and new version with stamp of the college you’ll be attending in Fall 2014)， 2) Visa Application Form DS-160 confirmation page， 3) Passport valid for at least six months before your departure date to the US; the expiration date on your passport should not change during the time between applying for visa extension/renewal and leaving China. In case it does， please provide updated ones along with the original expired one(s); 4) Previous U.S. student visas or I-94 forms which are still valid. Please make sure that they are valid when renewing your F1 visa， but will expire within a year after you get back from the United States；5) Proof of financial support such as bank statements showing sufficient funds deposited into my account；6) Letter from my sponsor stating his name、address（including zip code）and contact details， explaining reasons why he is willing to continue supporting me financially while I’m studying in the USA；7) Letters containing recommendations by two professors who have taught me recently；8) Transcript showing courses enrolled this semester and grades earned（if any）；9) Confirmation email about enrollment issued by the school；10) Receipt indicating payment of application fee. 11) Photo of size 5x5 inches， no sunglasses allowed. If photos were taken more than six months ago， we must submit another set of recent ones. It would also help if you could provide some other documents that can demonstrate how life has changed since coming to the U.S. For example，if you got married over there last summer， take pictures of your wedding invitation card / marriage certificate and show them to the consular officer. If you bought an apartment last spring，please bring those related papers as well.
12) A letter from our university advising us that we will attend their classes in September this year， together with evidence confirming our admission to study on campus（a hardcopy of acceptance letters would be best，but a scanned copy uploaded onto online applications system like Google Drive or Dropbox is acceptable too）