转向灯及危险报警灯闪光频率应为（）Hz。
A.2±O.5
B.1±O.5
C.1.5±0.5
参考答案：C
Mum, you really need to have a rest! You in the kitchen ever since you came back home three hours ago.
A．had worked
B．were working
C．have been working
D．worked
人的现实性有哪些表现？
