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Wood has many great characteristics that make it the perfect building material.It is cheap，durable，easily available，and most importantly，environmentally sustainable.The one thing it is not，is transparent! Now thanks to a team of scientists at Stockholm’s KTH Royal Institute of Technology the material may even be able to add that feature to its already impressive list.Lead researcher Dr，Lars Berglund said he was inspired to create the transparent wood after learning how Japanese researchers had developed a see-through paper for use in flexible display screens for electronic device请你拿出一枝圆柱形的完整铅笔和一枝削好的圆柱形铅笔．仔细观察和分析，看看你能从中发现哪些圆柱和圆锥的知识．并利用这些知识整理和复习本单元你所学到的知识．