MSC-51系列单片机指令系统中，最多有（）字节指令。
A、2
B、3
C、4
D、5
参考答案：B
On AIDS Day, the minister of Health Department demanded that the problems _____ paid special attention to.
A．referred to being
B．referred to be
C．refer to being
D．refer to be
对称三角形一般应有六个转折点，才能确认。（）
