I have experienced spells of heavy drinking, pure abstenance, and finally moderation throughout my life, and thoroughly enjoyed each. Drinking, as Pelihu pointed out, is the expected norm to open up a little and build trust to usually clinch a big deal. You will find this is almost always the case in China. Even during non-drinking phases, I felt compelled to have at least one shot of baijo to break the ice while a fellow colleague downed bottles and bottles. After two shots or so I would cliam that the liqueur is simply too strong and switched to a seltzer with lime. It looked like a gin and tonic to everyone else, which was good enough to get through the client entertainment portion of the evening.
In b-school you will stand out if you make an issue about being a Puritan. One option is to volunteer whenever possible as the group's designated driver. Doing so will entitle you to all the free non-alcoholic drinks you heart desires.
If everybody is cabbing home or you find yourself in a situation where you need to drink in order to feel accepted (again peer pressure), then order a crown seven and try to catch the waitress before she repeats your order to the bartender. Mention that you would like your's "very light on crown, please" as you work your way to the restroom. Nurse that C7 for an hour or so, by which point everybody else will be buzzing and won't notice that you reordered a generic 7up with a twist.
Seriously though, if you are uncomfortable drinking completely (not a single drop) then that's your prerogative, however you will be the oddball. IMO, the essence is to savor a good glass of Bordeaux, local microbrewed beer, or single shot of quality aged scotch, in proper moderation. It enhances the tastes of food, relaxes the nerves and helps lift the occational harmless inhibition.