θ波的频率为()
A.4~7Hz
B.1~4Hz
C.8~12Hz
D.15~20Hz
E.20~30Hz
参考答案:A
There is __of water in the bottle. You can drink.[ ]
A. a bit
B. a little
C. not a bit
D. not a little
()考勤机一般比较常见的。
A.打卡式
B.射频
C.指纹