材料一：2016年7月9日，生态文明资阳国际论坛2016年年会在贵阳市举行，本次年会以“走向生态文明新时代：绿色发展•知行合一”为主题，顺应了世界生态文明建设的趋势和潮流，展现了中国推动绿色发展、建设生态文明的务实行动，具有重要意义。

材料二：2016年12月25日，全国人大常委会表决通过了《中华人民共和国环境保护税法》，并将于2018年1月1日开始实施，环保税法是落实税教法定原则后，我国第一部“绿色税法”。环保税法开征环境保护税是贯彻党的十八届五中全会确立的绿色发展理念的具体体现，有利于减少污染物的排放，推进生态环境保护和生态文明建设。

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    The guzheng is a traditional Chinese musical instrument. It belongs to the zither（齐特琴）family of string instruments. It is the parent of many musical instruments of some other countries.

    The guzheng should not be confused with the guqin, another ancient Chinese zither but without bridges. Now the guzheng is zither with movable bridges and usually 21 strings, although it can have from 15-25 strings. The guzheng's strings were formerly made of silk, though most players used metal strings by the 20^th century. Since the mid-20^th century most performers use steel strings. The guzheng has a large resonant cavity（共振腔）.

    The guzheng has existed since the Warring States Period and became especially popular during the Qin dynasty. The number of strings on the guzheng has always fluctuated. There were as few as 6 to as many as 23 strings during the Tang dynasty. The earliest record of the guzheng belonged to the historian Sima Qian. Until 1961, the common guzheng had 16 strings, although by the mid-20^th century 18-string guzheng were also in use. In 1961, Xu Zhenggao, together with Wang Xunzhi, introduced the first 21-string guzheng after two years of research and development. In 1960, they also invented the “S-shaped” left string rest, which was quickly adopted by all guzheng makers and is still used today. This curve allows for greater ease in tuning the strings and, combined with strings of different thickness, allows for greater resonance in both the deeper and the higher pitch（音调）ranges. The 21-string guzheng is the most commonly used one, but some traditional musicians still use the 16-string one.