They do this by doing well-informed about their subjects, being honest in what they say, by using sound evidence, and by employing()reasoning.
A. valley
B. value
C. vary
D. valid
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未受或者尽量少受人类活动,特别是人为污染影响的土壤化学元素的自然含量称为()。
A. 土壤组成
B. 土壤成分
C. 土壤环境背景值
D. 土壤环境容量
Vehicles()only the simplest of the engine improvements that methanol makes feasible would still contribute to an immediate lessening of urban air pollution.
A. corporate
B. cooperating
C. operating
D. incorporating
《污水综合排放标准》中,第二类污染物质的排放标准按照其排放水域的使用功能以其企业性质共分为()标准值。
A. 二级
B. 三级
C. 四级
D. 五级
大气型土壤污染物主要集中于()。
A. 土壤里层
B. 土壤表层
C. 心土层
D. 底土层