1 . The 187-foot-tall Tower of Pisa is famous all over the world mainly because it leans (倾斜). For many years, people believed that the tower’s designer intended it to lean. As it turns out, though, the tower’s lean is an accident caused by poor planning. The Tower of Pisa was constructed (建造) on a riverbed of sand and clay (黏土) that was not strong enough to support a building so tall and heavy.
Construction of the tower began in 1173. Because Pisa experienced several wars, the tower wasn’t completed until 1350. Only a few years after the construction started, people could see that the first three floors of the tower were already leaning. As the next three floors were added, builders purposefully built them with one side higher than the other to try to correct the lean. This resulted in the tower leaning in the opposite direction
Fortunately for the people of Pisa, the long delays (耽搁) during construction gave the structure time to settle and the ground to become compacted (结实的). This mad the foundation (地基) stronger over time, which is the main reason why the tower never fell over. For hundreds of years, the tower was indeed falling. It would lean one more inch about every 20 years. In the end, in 1990, it was closed to the public for fear that a large group of people at the top would weigh enough to make it fall down.
From 1990 to 2001, engineers from around the world helped balance the tower After several unsuccessful attempts at a solution, engineers finally came up with a plan that worked. They slowly removed ground under the high side of the tower. When they had finished, they had returned it to the position it held in about 1838—the tower had been straightened by nearly 16 inches. Except a sudden great disaster, such as a earthquake, engineers believe the tower is safe for another 300 years now.
1. What does the author try to explain about the Tower of Pisa in Paragraph 1?| A．Why it leans. | B．Why it was built. |
| C．Why it is famous. | D．Why it stopped leaning. |
| A．It was completed in 1173. | B．It began to be built in 1350. |
| C．It was seen leaning after 1173. | D．It was repaired every 20 years. |
| A．The special structure. | B．The timely protection. |
| C．The skill of the builders. | D．The long time of building. |
| A．When does the Tower of Pisa lean? |
| B．Is the leaning Tower of Pisa falling? |
| C．When was the leaning Tower of Pisa built? |
| D．How did the leaning Tower of Pisa get its name? |
