The tower of Pisa has never been upright. Its leaning can date back to the time not long after it was built in 1173. First, the tower tilted towards the north. Then during the prolonged process of construction till 1370, the tower had always been leaning to the south.
Throughout the monument s history, many efforts have been made to halt the lean. These efforts have so far helped prevented the tower from topping over. But since 1911, the offset at the top of the tower has increased at a fairly consistent rate. Shortly after 1989, for the sake of safety, the tower at Pisa was closed to visitors.
In 1990, a special commission was organized to find new ways to save the tower. At first the commission worked mainly on the outside of the tower, but in the next few months, more radical techniques will be tried to stop the tower s lean. The ultimate goal is not to straighten the tower but to ease its top back a little. With luck, the landmark can stand into the next century.
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阶梯英语歌谣:再做一次
一年级英语学习口语教程:Four
一年级英语学习口语教程:Three
阶梯英语歌谣:今天来聚会吧
一年级英语学习口语教程:Seven
阶梯英语歌谣:15只小鸟
一年级英语学习口语教程:Eight
阶梯英语歌谣:我们一起去花园吧!
一年级英语口语绝佳句型100句(3)
一年级英语学习口语教程:Six
阶梯英语歌谣:在公园度过美好的一天
小学一年级英语口语练习:问答1
阶梯英语歌谣:我准备好了
小学英语口语:Come on
阶梯英语歌谣:在客厅
一年级英语学习口语教程:One
阶梯英语歌谣:变戏法
小学一年级英语口语练习
阶梯英语歌谣:写说拼擦
阶梯英语歌谣:听我说
阶梯英语歌谣:非常感谢你
小学一年级英语口语练习:问答2
一年级英语口语绝佳句型100句(1)
一年级英语口语绝佳句型100句(2)
阶梯英语歌谣:数字1至5
阶梯英语歌谣:我很喜欢
阶梯英语歌谣:我跳得很高
阶梯英语歌谣:苹果橙子番茄土豆
阶梯英语歌谣:我爱我家
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