Today we take for granted that the mail will be delivered __1__ daily at our door. But many years ago it might have been placed in a tree trunk and underneath a rock. In the early __2__ days of the mail no one could be sure about where or when it will arrive. __3__ At the southern tip of Africa there was once a post office under a rock. At the old days the route from England to __4__ India was around the Cape of Good Hope. The journey was stormy and danger. It took six long months. Sailors often __5__ 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 __6__ stone scratched the words “Look here under for letters.” __7__ They would leave their letters there, knowing that the next homeward ship would stop and pick it up. __8__ There was another post office like this at the southern tip of South America. During the golden rush days, boats __9__ sailed around Cape Horn to California. At Cape Horn was a keg(小桶) 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. __10__