6．
According to the US government，wind farms off the Pacific coast could produce 900gig watts of electricity every year．Unfortunately，the water there is far too deep for even the tallest windmills（see picture）to touch bottom．An experiment under way off the coast of Norway，however，could help put them anywhere．
The project，called Hywind，is the world's first large-scale deepwater wind turbine（渦輪發電機）．Although it uses a fairly standard 152-ton，2.3-megawatt turbine，Hywind represents totally new technology．The turbine will be fixed 213feet above the water on a floating spar（see picture），a technology Hywind's creator，the Norwegian company StatoilHydro，has developed recently．The steel spar，which is filled with stones and goes 328feet below the sea surface，will be tied to the ocean floor by three cable（纜索）；these will keep the spar stable and prevent the turbine from moving up and down in the waves．Hywind's stability（穩定性）in the cold and rough sea would prove that even the deepest corners of the ocean are suitable for wind power．If all goes according to plan，the turbine will start producing electricity six miles off the coast of southwestern Norway as early as September．
To produce electricity on a large scale，a commercial wind farm will have to use bigger turbines than Hywind does，but it's difficult enough to balance such a large turbine so high on a floating spar in the middle of the ocean．To make that turbine heavier，the whole spar's to design a new kind of wind turbine，one whose gearbox（變速箱） sits at sea level rather than behind the blades （see picture ）
Hywind is a test run，but the benefits for perfecting floating wind-farm technology could be extremely large．Out at sea，the wind is often stronger and steadier than close to shore，where all existing offshore windmills are planted．Deep-sea farms are invisible from land，which helps overcome the windmill-as-eyesore objection．If the technology catches on，it will open up vast areas of the planet's surface to one of the best low-carbon power sources available．
63．The Hywind project uses totally new technology to ensure the stability ofB．
A．the cables which tie the spar to the ocean floor
B．the spar which is floating in deep-sea water
C．the blades driven by strong and steady sea wind
D．the stones filled in the spar below the sea surface
64．To balance a bigger turbine high on a flatting spar，a new type of turbine is to be designed with its gearbox sittingC．
A．on the sea floor B．on the spar top
C．at sea level D．behind the blades
65．Wide applications of deepwater wind power technology canD．
A．solve the technical problems of deepwater windmills
B．make financial profits by producing more turbines
C．settle the arguments about environmental problems
D．explore low-carbon power resources available at sea．
