It is{#blank#}1{#/blank#}(say) that an earthquake happened 2,000 years ago in China. The earthquake happened {#blank#}2{#/blank#}(all of a sudden){#blank#}3{#/blank#}(without doubt), a lot of people died in this accident. At that time, a man named Zhang Heng decided{#blank#}4{#/blank#}(invent) something to stop people from {#blank#}5{#/blank#} (die) in an earthquake. He tried many times. At last, he succeeded. It{#blank#}6{#/blank#}(be used for) knowing about which place would have an earthquake. If an earthquake {#blank#}7{#/blank#}(happen) in the west, the ball in the western dragon's mouth of the {#blank#}8{#/blank#}(instrument) would fall. The story about Zhang Heng and his instrument {#blank#}9{#/blank#}(translate into) many languages. I think it's really a great{#blank#}10{#/blank#} (invent) in the world.