根据《污水综合排放标准》，总汞的最高允许排放浓度限值是（）mg/L
A.0.005
B.0.05
C.0.1
D.0.5
参考答案：B
Which of the following statements concerning the current yield is CORRECT It:（）
A. is of great interest to conservative bond investors seeking current income.
B. is of great interest to aggressive bond investors seeking capital gains.
C. shows the rate of return an investor will receive by holding a bond to maturity.
连挂车辆，显示十、五、三车距离信号后，在距离停留车五、三、一车前，应分别将速度降至不超过15km/h、10km/h、5km/h；连续连挂不得超过（）
A、5km/h
B、10km/h
C、15km/h
