根据CT值的定义公式，空气的CT值为（）
A.－700HU
B.－800HU
C.－900HU
D.－1000HU
E.－1100HU
参考答案：D
The Changbaishan Mountains have a huge variety of scenery, some of the best of _____ can only be reached
on foot. [ ]
A. that
B. which
C. what
D. where
在一定条件下，下列粒子的还原性顺序为：
Cl-＜Br-＜Fe2+＜I-＜SO2，由此判断下列各反应在溶液中不能发生的是
A．2Fe3++SO2+2H2O====2Fe2+++4H+
B．2Br-+4H++====SO2+Br2+2H2O
C．2Fe2++Cl2====2Fe3++2Cl-
D．I2+SO2+2H2O====4H+++2I-
+4H+