阅读下面的短文,根据短文的内容在每个空格上填上一个形式正确、意思相符的单词。 In the 13th century, the famous Italian traveler, Marco Polo, traveled to China. During his stay in China, he discovered {#blank#}1{#/blank#} the Chinese used paper money. In western countries, people didn't use paper money {#blank#}2{#/blank#} 15th century. {#blank#}3{#/blank#}, people in China began to use paper money in the 7th century. A Chinese man called Cai Lun {#blank#}4{#/blank#} paper about 2 000 years ago. He put these pieces of paper together and made them into a book.
We use a lot of paper every day. If we keep on {#blank#}5{#/blank#}so much paper, there will be no paper. So how can we save paper? We can use {#blank#}6{#/blank#}sides of every piece of paper. We can choose drinks in bottles {#blank#}7{#/blank#}of those in paper packets(小包). We can {#blank#}8{#/blank#} use handkerchiefs(手帕) and not paper ones. When we go shopping we can use fewer paper bags. {#blank#}9{#/blank#} the shop assistant gives you a paper bag, we can save it and reuse it later.
{#blank#}10{#/blank#} has the duty to help to save paper. We should do it now, before it is too late.