docs: public TPredict classify(Instance instance, int n){
  		LinkedPredict<String>  pred = new LinkedPredict<String>(k);
  
  		for(int i = 0; i < prototypes.size(); i++){
  			Instance curInst = prototypes.get(i);
  //			if(((String) curInst.getSource()).contains("听#per#的歌"))
  //				System.out.println("");
  			float score;
  			try {
  				score = sim.calc(instance.getData(), curInst.getData());
  			} catch (Exception e) {
  				// TODO Auto-generated catch block
  				e.printStackTrace();
  				return null;
  			}
  			pred.add((String) curInst.getTarget(), score,(String) curInst.getSource());
  		}
  		//排序
  		LinkedPredict<String> newpred = pred.mergeDuplicate(useScore );
  		newpred.assertSize(n);
  		return newpred;
  	}