Have any of the parents taken you out to special pre-school year dinners? They have to me and alot of my colleagues. On top of the very, very expensive dinner have you ever been given a red envelope by a parent that has a 500 yuan card inside of it? I have. That was to "apologize in advance for their children's behavior." It was certainly not a bribe. Granted that some of my colleagues do work alot more hours than me, but the theme of my story is that Chinese teachers earn alot more than the salary you stated. I asked one such teacher what she did this summer and she told me "Taught English at home." In Jiangsu province private teaching is ilegal by public school teachers.

Lets do the math:

parent hong baos (red envelopes)which may vary from year to year
summer teaching at home
end of year bonuses
pay for test results
teacher day bonuses (some as much as a few months salary to avoid paying income taxes)
pension (I got none)
insurance (a whole lot better than mine)
pay over 12 months ( I get 11 months)

It all adds up to a good package with a nice mix of grey money. My first year in CHina my total compensation was 70,000. My ex was well over 100 k. I work in a small town of 500,000 people now. One of my colleagues just bought a new 800,000 yuan house with a 500,000 down payment he made from selling his old house. He is an English teacher in his early 30s with 10 years experience. I hang out with my colleagues here, and after they trust you a bit it's incredible how much they share with you.