题目内容
土壤环境背景值指在自然状况或相对不受直接污染情况下土壤中化学元素的正常含量。一般应在远离污染源的地方采取样品,测定化学元素含量,并运用数理统计方法检验分析结果,然后取分析数据的平均值或数值范围作为背景值。()是环境科学的一项基础性工作,是环境质量评价和预测污染物在环境中适移转化机理,以及土壤环境背景值一定程度上反映了土壤环境的质量。一般在某一地区,如土壤环境背景值比较稳定,则可相当程度上表明这一地区的环境质量较为稳定;反之亦如此。同时,土壤背景值也一定程度上影响和决定了土壤环境的当前质量。
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As more women in the United States move up the professional ladder, more are finding it necessary to make business trips alone. Since this is new for many, some trips are certainly in order. If you are married, it is a good idea to encourage your husband and children to learn to cook a few simple meals while you are away. They will be much happier and probably enjoy the experience. If you will be eating a good meal alone, choose good restaurants. In the end, they will be much better for your digestion (消化). You may also find it useful to call the restaurant in advance and state that you will be eating alone. You will probably get better service and almost certainly a better table. Finally, a/ad most importantly, anticipate (提前做准备) your travel needs as a business woman; this starts with lightweight luggage which you can easily manage even when fully packed. Take a folding (折叠) case inside your suitcase; it will come in extremely handy (极其方便) for dirty clothes, as well as for business documents and papers you no longer need on the trip. And make sure you have a briefcase so that you can keep currently required papers separate. Obviously, experience helps ,but you can make things easier on yourself from the first by careful planning, so that right from the start you really can have a good trip!
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