简述普通股与优先股的基本特点。

A. UP控制器、存储器和I/O设备
B. 运算器、控制器、存储器和UPS
C. 运算器、控制器、存储器和I/O设备
D. 运算器、控制器、存储器

A single row subquery can retrieve data from only one table.
B. A SQL query statement cannot display data from table B that is referred to in its subquery, unless table B is included in the main query's FROM clause.
C. A SQL query statement can display data from table B that is referred to in its subquery, without including table B in its own FROM clause.
D. A single row subquery can retrieve data from more than one table.
E. A single row subquery cannot be used in a condition where the LIKE operator is used for comparison.
F. A multiple-row subquery cannot be used in a condition where the LIKE operator is used for comparison.

A. 8.2
B. 9
C. 10
D. 11.1

A. 线性失真和非线性失真
B. 频率失真和相位失真
C. 截止失真和饱和失真