code: public static List<Term> getSubTerm(Term from, Term to) {
  		
  		List<Term> subTerm = new ArrayList<Term>(3);
  
  		while ((from = from.to()) != to) {
  			subTerm.add(from);
  		}
  
  		return subTerm;
  	}
docs: 从from到to生成subterm
  
  @param from
  @param to
  @return