土壤污染
QoS policies are applied on the switches of a LAN. Which type of command will show the effects of the policy in real time?（） [" show command"," debug command"," configuration command"," rommon command"]
城市水体污染的控制和治理技术有哪些方法？
矿化作用
一国某年末外债余额43亿美元，当年偿还外债本息额14亿美元，国内生产总值325亿美元，商品劳务出口收入56亿美元，则偿债率为（）。 ["4.30%","32.56%","56%","4%"]
富集系数
