按下一个键后立即放开，产生IRQ1的个数是( )
A．随机的
B．1
C．2
D．3
参考答案：C
— Hello! May I speak to Kate?
— Sorry, she isn't here now. She ______ to Shanghai. [ ]
A. went
B. has been
C. has gone
市场细分的原则有什么特点？
