填空题
Today we take for granted that the mail will
be delivered daily at our door.But many years ago
it might have been placed in a tree trunk and 【M1】______
underneath a rock.In the early days of the mail no
one could be sure about where or when it will arrive 【M2】______
At the southern tip of Africa there was once a
post office under a rock.At the old days the route 【M3】______
from England to India was around the Cape of
Good Hope.The journey was stormy and danger.
It took six long months.Sailors often wished to 【M4】______
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 【M5】______
stone.On the stone scratched the words ’Look 【M6】______
hereunder for letters.’They would leave their letters
there，knowing that the next homeward ship 【M7】______
would stop and pick it up.
There was another post office like this at the
southern tip of South America.During the golden 【M8】______
rush days，boats sailed around Cape Horn to
California.At Cape Horn was a key（小桶）nailed to a
post.Boats coming from the east coast would send
for some sailors to this post office.They picked up 【M9】______
any letters in the key.At the same time they
mailed letters home that boats sail east could pick 【M10】______
up.