On-lineconcentration techniques have been employed more and more in many analytical areas over the past decade due to their advantages of simplicity, automation, low cost and high sensitivity.
They continue to manipulate various factors, such as concentration and frequency, vainly trying to draw a parallel line between the animals and humans when there isn't one.
他们继续控制各种因素，如浓度和使用次数，妄图在动物和人类之间做比较，而这种可比性是不存在的。
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Keeping track of these time shifts takes concentration, since theauthor will sometimes deliberately blur the line between war as grand drama andwar as farce.