code: public String text(String delimiter)
      {
          if (delimiter == null) delimiter = "";
          StringBuilder sb = new StringBuilder(size() * 3);
          for (IWord word : this)
          {
              if (word instanceof CompoundWord)
              {
                  for (Word child : ((CompoundWord) word).innerList)
                  {
                      sb.append(child.getValue()).append(delimiter);
                  }
              }
              else
              {
                  sb.append(word.getValue()).append(delimiter);
              }
          }
          sb.setLength(sb.length() - delimiter.length());
  
          return sb.toString();
      }
docs: 原始文本形式（无标注，raw text）
  
  @param delimiter 词语之间的分隔符
  @return