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Plastic is one of the most important technological discoveries of the 20th century．However．it may soon be replaced．The new development――liquid wood――can replace plastics in a11 branches of modern―day industries．

Plastic as a material enjoys the biggest demand in the modern world，but it does have a number of drawbacks．First and foremost，plastic isn’t recyclable．Secondly，it contains toxins(毒物)helping develop cancerous diseases．Finally，it's made of oil and oil reserves aren’t endless．

The liquid wood technology is likely to replace plastic and providing mankind with new materials for many years ahead．Norbert Eisenfreich．a senior researcher at the Faunhofer Institute for Chemical Technology in Germany(ICT)，said that arboform，the new material，is made of lignin(木質素)，which can be obtained from soft tissues of wood．Once mixed with several other materials，it turns into solid and nontoxic alternative for plastics．

ICT team leader Emilia Regina Inone――Kauffmann said the wood-working industry separates wood into three basic components，including lignin．Lignin isn’t used for the production of paper．Specialists of ICT mixed lignin with several natural materials and thus invented the material which could be melted(熔化)and molded(鑄型)．

When solid，arboform looks like plastic and possesses the qualities of polished wood．It can be used for the production of any items．Arboform is already used for the production of car parts which require extra strength．In addition，liquid wood can be recycled repeatedly．he material preserved all of its qualities even if it’s reprocessed ten times．

However，the new invention doesn’t enjoy an extensive use due to the high content of sulphur(硫)in it．German researchers are sure to reduce the amount of sulphur by 90 percent very soon to make arboform usable for ho，me needs．

7 1．According to the passage，plastics              ．

    A．does harm to our society in some way

    B．helps to protect our environment in some way

    C．has been replaced by the newly discovered material

    D．helps US to reduce the use of petrol

 72．The underlined word“alternative”in Paragraph 3 refers to            ．

    A．hgnin or arboform                 B．plastics

    C．mixture of several materials          D．soft tissues of wood

 73．What’s the advantage of arboform over plastic?

    A．It is easier made from natural oil．

    B．It is more widely used in household．

    C．It is recyclable and friendly to environment．

    D．It contains no poisonous materials．

74．It can be concluded that German researchers will focus their future work firstly on            ．

    A．the material’s extensive use         B．the content of sulphur in arboform

    C．the production cost of arboform   D．the qualities of liquid wood

 75．The main purpose of the text is to              ．

    A．advertise the new material――arboform

    B．introduce liquid wood which will replace plastic

    C．advertise new products made of arboform   

    D．show readers how to produce arboform