private void addEnd(Cell pre, Cell last) {
		int end_tag = ergate.core.Tag.TagMapper.tag2I(ergate.core.Tag.SE);
		int next_tag = ergate.core.Tag.TagMapper.tag2I(last.tag);
		wt_num++;
		Tag tag = tagMap.get(next_tag);
		if (tag == null) {
			tag = new Tag();
			tagMap.put(next_tag, tag);
		}
		tag.trans.addBranch(end_tag, 1l);// 添加end->end标签，以计算end的频率

		Word w = getWord(last);
		if (w == null) {
			w = createWord(last);
		}
		w.r_relate.addBranch(w.id, 1l);// 添加eos-eos标签,以计算eos的频率
		NumMap rtag = w.tags.get(next_tag);
		if (rtag == null) {
			rtag = new NumMap();
			w.tags.put(next_tag, rtag);
		}
		rtag.addBranch(end_tag, 1l);// 添加eos->end->end标签,以计算eos->end的频率
	}