The variograms of arsenic persistently increased and could be fitted by exponentialequation.
土壤砷含量半方差值呈有规律持续增加趋势，可用指数方程很好地拟合。
2
The results show that the COD at the inflow and outflow follows the rule of exponentialequation.
结果表明，湿地进出水COD服从指数方程规律。
3
Through mathematic analysis, the author of this paper comes to a conclusion that negative exponentialequation can not be used to elucidate the regularity of the settling of suspended matter.