六级冲刺备考的改错练习（18）

　　第十八篇： Error Correction

　　Today we take for granted that the mail will be delivered --71--

　　daily at our door. But many years ago it might have been

　　placed in a tree trunk and underneath a rock. In the early --72--

　　days of the mail no one could be sure about where or when it will arrive. --73--

　　At the southern tip of Africa there was once a post office --74--

　　under a rock. At the old days the route from England to

　　India was around the Cape of Good Hope. The journey was

　　stormy and danger. It took six long months. Sailors often --75--

　　wished to send mail home, but they seldom met ships bound

　　back to England. So at the cape the sailors would go on

　　ashore. They headed for a certain large stone. On the --76--

　　stone scratched the words Look hereunder for letters. --77--

　　They would leave their letters there, knowing that the

　　next homeward ship would stop and pick it up. --78--

　　There was another post office like this at the southern

　　tip of South America. During the golden rush days, boats --79--

　　sailed around Cape Horn to California. At Cape Horn was

　　a keg nailed to a post. Boats coming from the east

　　coast would send some sailors to this post office. They

　　picked up any letters in the keg. At the same time they

　　mailed letters home that boats sail east could pick up.--80--