电动潜油泵井日产液量达到或超过100t的，正常波动范围是±（）。
A、3%
B、5%
C、10%
D、15%
参考答案：B
The teacher couldn't make himself _____ attention to because the students were so noisy. [ ]
A. to pay
B. to be paid
C. paid
D. pay
正值农忙季节，农田需要大量的灌溉用水，若水泵在0.5h内把360m3的水抽到5m高处（g取10N/kg），则水泵对水做功的功率至少为 [ ]
A．1.8×106J
B．3.6×106W
C．10kW
D．3.6×107W
