The Big Ben is very famous throughout the world, but nobody really knows the reason why it is called Big Ben. However, there are two stories may explain the reason. Some people say that it was __1__ named Benjamin Caunt, a boxer, who was called Big Ben. __2__ More people believe the name comes from a Welshman,Sir Benjamin Hall. __3__ He commissioned the work in 1859. A story arose that, during a debate in House of Commons on what to call the bell, Sir Benjamin was about __4__ to give his ideas that someone who sat behind the front bench shouted, __5__ "Let's call it Big Ben!"
The history of the bell tower, since the beginning of its design, is by no means smooth, however. Due to disagreements about the clock's design, it takes fifteen years to build. In 1857, the structure was __6__completed and tested on the ground, but a four-foot crack appeared,and the bell had to cast again. Finally, the clock started ticking __7__ on May 31,1859, and stroke its first chime on July 11. Then, in __8__ September, the bell cracked again. It was silent for four years but was eventually turned a quarter of a revolution. As a result,the crack was not under the striking hammer. Craftsmen made a square above the crack to stop it to cracking further and it can __9__ still be seen today.The Big Ben is famous not only for its thirteen-ton weight, but also for its accuracy, that is a result of its presise mechanism. __10__ Even one extra penny's weight on the balance would cause a gain of two fifths of a second in twenty hours. Although there have been several problems, the bell still chimes today.