改变bash的提示符实际上就是改变变量（）。
A.$HOME
B.$PWD
C.$PS1
D.$PS2
参考答案：C
---Why do you look so worried?
---I’m expecting a call from my son. He London for three days.
A．has been to
B．has been in
C．has gone to
D．has come in
菲罗忒斯
