摄像机机参数中的BLC代表（）
A.自动增益
B.背光补偿
C.电子快门
D.信噪比
参考答案：B
若∠A ＝ 20°18′，∠B ＝ 20°15′30〃，∠C ＝ 20.25°，则（ ）
A．∠A＞∠B＞∠C
B．∠B＞∠A＞∠C
C．∠A＞∠C＞∠B
D．∠C＞∠A＞∠B
If event A and event B cannot occur simultaneously, then events A and B are said to be:（）
A. collectively exhaustive.
B. statistically independent.
C. mutually exclusive.
