From the earliest times，man has been interested in art．People have often worked together to collect and save the world's art treasures．
Fine art treasures from many countries are kept in an art museum called the Louvre in Paris，France．The works of art have been collected by the people of France over many centuries．
The Louvre has not always been a museum．The first building was a fort（炮台）．In 1190，it was the king's castle with high walls and a round tower．It had a moat to keep out his enemies．
Over the years，the number of buildings around the castle grew．By 1350，the castle was no longer needed as a fort．The Louvre became a palace home for French kings and queens．
During times of peace，new treasures were brought in．During days of war，many treasures were stolen，and the buildings were damaged．
When Francis I became king of France in 1515，he brought in artists from many countries．One of the artists was Leonardo Da Vinci from Italy．Da Vinci's"Mona Lisa"is the best known painting in the museum today．
In 1793，the Louvre became a public museum，just as it is now．It is a place where art treasures have been saved for everyone to enjoy．
46．On the whole，this passage is mainly about____. ．
A ．an art museum called the Louvre          B ．an Italian artist named Leonardo Da Vinci
C ．a king of France named Francis I          D ．the best known painting in Louvre
47．Which of the following is not true？
A ．The Louvre used to be a fort a very long time ago．  
B ．French kings and queens once lived in it．
C ．The Louvre was taken by enemies in 1190． 
D ．Many treasures were brought into the Louvre over the years．
48．Why is it good for great art to be kept in public museums？
A ．It helps people remember who the King of France is．
B ．It keeps people out of the palaces．
C ．It gives everyone a chance to enjoy good art．
D ．It helps people to know who is the greatest artist．
49．From the passage we know that _____．
A ．It is not possible for treasures to be stolen
B ．Old forts always make the best museums
C ．Great art should be shared with all the people
D ．King Francis I of France brought in artists from an old fort
50．In the third paragraph the word "moat" probably means_____．
A ．a high tower built in former times where soldiers watched out for enemies
B ．a long and deep ditch(沟) dug round a castle and was usually filled with water
C ．a cart pulled by horses on which soldiers fought
D ．a long and high wall around castle