[示例1]去年在洪水中被毁的那座桥已被重修了。
一般句：The bridge which was destroyed in the flood last year has been rebuilt.
升级句：The bridge destroyed in the flood last year has been rebuilt.(过去分词作定语)
[示例2]我不喜欢排长队，那是浪费时间。
一般句：I don't like waiting in a long queue.It is a waste of time.
升级句：Waiting in a long queue is a waste of time.(动名词作主语)
