docs: public void toBMES(String file,int duplicateNum) throws IOException {
  		BufferedWriter bout = new BufferedWriter(new OutputStreamWriter(
  				new FileOutputStream(file,true), "UTF-8"));
  		for(String line:set){
  			if(line.length()>1){
  				StringBuilder sb = new StringBuilder();
  				for(int i=0;i<duplicateNum;i++){
  					sb.append(line);
  					if(i<duplicateNum-1)
  						sb.append(" ");
  				}
  				line = sb.toString();
  			}
  			String s = Tags.genSegSequence(line,"\\s+",4);
  			bout.write(s);
  		}
  		bout.close();	
  	}