【单选题】正常雨水的pH约为5.6,酸雨的pH一般小于5.6.下列有关酸雨的论述不正确的是( )
B.
正常雨水也有微酸性,这是由于溶有CO 2 的缘故
C.
酸雨中因含有亚硫酸,其pH会慢慢下降到一定值
【单选题】If there is perfect certainty, a competitive firm will necessarily:
A.
seek to maximize its immediate profits rather than long run returns because otherwise it will go broke.
B.
maximize the ratio of the present value of its sales to the present value of its costs.
C.
equalize its profits in all periods.
D.
equalize its sales in all periods.
【简答题】(1)酸雨的PH值一般是小于 ____的天然降水。酸雨主要是人为的向大气中排放大量的二氧化硫和氮氧化物等物质所造成的,酸雨中的绝大部分是硫酸和硝酸; 请同学们写出二氧化硫与水反应的方程式:____
【判断题】护理员协助老年女性取仰卧位,掀开下身盖被折向近侧,协助其脱下裤子至膝部
【判断题】酸雨一般指pH值小于5.6的各种形式的降水。