In the Fall I will be going to teach English in China. At the moment I have two contracts from two places, on?

e is a High School and the other is a University. I have signed both contracts, but I'm still in U.S., not China. I've read that these aren't formal contracts, from this email that a guy, an agent sent, from another company, but I want to ask, well, I'm thinking that I want to refuse the High School offer because the Uni seems much better. I only have to teach 15 cles at the Uni for the same pay that the High School asks for 20 to 25 cles, a week (pay is 5000 in both). What should I write to the High School place? How should I refuse that? Will I still be penalized in some way? Also, I have two Bachelors, one in English and one in Philosophy, and an Art HIstory Minor; I've tutored in the Writing Center of my University for a year and I've been a teacher's istant at this cl for ESL adult learners this past semester. However, I'm still afraid that I won't know how to teach these students, especially at a Univeristy. It's oral english, but should I be worried? Should they provide me with some kind of curriculum? Also, the reason I have told either HS or Uni about thinking of the other place is because I don't want to keep all of my eggs in one basket, in case something happened and I couldn't go to the place. The high school person says she's going to be sending me the school's doents here in U.S. I'm thinking that I could always say something to this H.S. person, and would they know about it? i mean why i couldn't come.