[填空题]
Some electric-power )nm*db 7s j c8y zxs9cw8me(z7companies use water to store energy. Water orql5p c gwx,.k77n r4is pumped by reversible turbine pumps from a low to a high reservoirprqng5774c kx,o.rwl . To store the energy produced in 1.0 hour by a 120-MW ($120\times10^{6}$W) electric-power plant, how many cubic meters of water will have to be pumped from the lower to the upper reservoir? Assume the upper reservoir is 520 m above the lower and we can neglect the small change in depths within each. Water has a mass of 1000 kg for every 1$m^3$. $m^3$
