1 . In each country, there are some places of interest, like Big Ben in Britain, the Great Wall in China and so on. So you must ______ the Leaning Tower of Pisa(比萨斜塔). But do you know why it leans (倾斜)? It leans ______ a mistake. In 1173, people of ______ wanted to build a bell tower. They wanted the tower to be ______ bell tower in the whole country. Before people finished ______ the third floor of it, the tower began to lean. People tried to make the building______ again. However, as they added(增加) more floors, the tower only got ______.

It ______ almost 180 years to finish the tower. Today, the Leaning Tower has eight floors. It’s 54.5 meters tall, and it leans about 5 meters to one ______. If someone cannot think out a good way ______ the tower, like all the other old buildings, it’ll fall apart(倒塌) in the future.