题目

Plastic is one of the most important technological discoveries of the 20th century．How    ever．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 plasti宣城市城区的鳌峰公园与宛溪河等改造已初见成效，而位于我们学校旁的梅溪公园的小湖以环种垂柳与观景亭廊而景胜一方，湖畔垂柳成萌，水面倒影如镜，见图．从物理学的角度看，“垂柳成荫”是由于光的    形成的，“倒影如镜”是由光的    所形成的岸边景物的    （选填“实像”或“虚像“）．