In China, there are always many interesting stories about inventions. Chopsticks are one of {#blank#}1{#/blank#}（important） inventions in Chinese history. Do you know the story behind the chopsticks? Let me tell you.

    According {#blank#}2{#/blank#}a famous story, Dayu, the Emperor of the Xia dynasty, was the person {#blank#}3{#/blank#}invented chopsticks. At that time there was a flood in China. Yu was very  {#blank#}4{#/blank#}（worry） about his people and the flood. And he tried his best {#blank#}5{#/blank#}（find） some ways to control the flood.

    One day, he was having his lunch at home  {#blank#}6{#/blank#}someone came and told him that the flood was coming again. He stopped {#blank#}7{#/blank#}（eat） and set out at once. He was hungry and wanted to pick up some meals on the table to eat {#blank#}8{#/blank#}（quick）. But the food was {#blank#}9{#/blank#}hot to pick up with hands. Then he used two branches（树枝） from a tree to pick up the food. They were the {#blank#}10{#/blank#}（one） pair of chopsticks.