问题
名词解释
正常剖面
答案
参考答案：
分布最广的土壤剖面构造类型，具有代表土壤形成过程的完整发生层，而且土层厚度正常。
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正常剖面
参考答案：
分布最广的土壤剖面构造类型，具有代表土壤形成过程的完整发生层，而且土层厚度正常。
| 任务性阅读。 | |
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| It is everyone's duty to protect the environment. Air pollution and 1 pollution are big problems. We should take daily actions to make the pollution 2 senous. We can control the way we choose to live and act on our neighborhood to reduce pollution. For example, if you don't litter here and there, streets will become cleaner. Also, if you don't spit on the gound 3 , the air will become 4 ; and if you ride to work instead of 5 , there will be less air pollution to protect ourselves. So let's do what we can to help protect our living environment. 任务A：用方框内所给的词的适当形式填空，使文章通顺、合理。 1._____ 2.______ 3.______ 4.______ 5.______ 任务B：根据英文释义及首字母提示，拼写单词。 6. s_____ more than two but fewer than many 7. c_____ to enjoy oneself usually for a special reason |
CH
。三聚氰胺也可以由氰胺（WXY分子中的W原子被氨基取代后可得氰胺）发生类似于乙炔的三聚反应而得到，三聚氰胺中无非极性键，含有三个氨基，请写出三聚氰胺的结构简式：_________________。 