8051单片机的运算器的组成部分包括( )。
A. 算术逻辑部件ALU
B. 累加器ACC
C. 计数器PC
D. 程序状态寄存器PSW
E. BCD码运算调整电路
Is ______Qinghai-Tibet Railway plays an important role in China’s railway history the topic that you are coming to?
A. what
B. it
C. this
D. that
Stage fright is a common example of _______educators call a “lack of confidence” among students.
A. that
B. what
C. which
D. whose
圆轴扭转时,横截面上的内力是扭矩。( )
A. 对
B. 错