I think, with Chinese teenagers especially, you need to behave in a somewhat casual manner - one of the problems of Chinese English-language teachers is, I think, too much formality, too much as an authority figure - learning a language is not just a matter of individually mastering some sort of rules, it's about interaction. The idea of 'forcing' them to give some response is not wrong, but it is easily overdone in a culture where pinning an individual down in front of his/her peers makes everybody freeze up and want to hide, so smile or be a bit casually humorous when you insist on answers from the picked-out individual whom you are putting on stage in front of everybody. Suggest you try to get somewhat loose conversation going (no, not so easy, but a lot will depend on your behavior as a not-too-authoritarian figure), mix it with some relevant non-threatening group repetitions of sentence structures and so forth. And you don't need to use a textbook, necessarily, but you do have to put in a little planning before class, so that you can lead into and away from individual responses by the use of some related structural practices, and/or throw in relevant grammar points. The most important thing to do is to get students to relax - note that every student in China has studied some English and very few of them become comfortable enough to experiment with it in any 'natural' manner, and most feel they're lousy with English and dislike studying it - and these things are mutually reinforcing.
I'm not criticizing anything you are presently doing because I don't know what it is, but the above is what has worked for me, for Chinese students. A little vague, perhaps, but remember, it's partly an acting job, on your part.
How many students in the class? The more there are over the number of about fifteen the harder it is to do this, and, well, that's a problem.
Their being under pressure for the gaokao is particularly a problem for oral language classes.

Geezer's got good practical sense.

@ laotou: culture & behaviors are always changing, and are doing so as we speak, and we're all contributing one way or another. I think it's good, as individuals, to be aware of that and own up to responsibility for it. Few people are ONLY victims.

Question: Why doesn't anybody give a damn about the Filipinos, Vietnamese and Malaysians who are affected?

@Dudeson: When governments grow powerful, they always pull this kind of crap (US Government vs. Chinese governments in the S. China Sea) - those who man the institutions that control nations do not stop bullying when they grow powerful - nothing to do with 'growing up', which is a species-wide problem affecting us both individually and collectively (necessarily, BOTH). This is a paranoid, aggressive, competitively-exploitative world system we live under, and the relative behavior of the major players is the secondary issue. After the species gets though the current, exceedingly dangerous nonsense, there will be more, no matter who comes out on top for the present, and sooner or later the whole species will be up the spout. I think most of us will probably get through the present crisis, but sooner or later the statistical odds will turn against all of us.
Unless...
Bets wishes to everybody, and good luck for as long as that lasts. In the meantime, try to understand how we all feed the Machine and try not to contribute.
In case anybody wants to waste all our time and make this personal, I'm not claiming innocence.
@laotou: Nice rant - don't think we need any more of the same ilk, from anybody, but I have to admit that some of it was interesting.