go to school.However,he could go to the library.William was at the library one day when he saw a book with windmills(风车)on the cover.He knew that a windmill used wind to make electricity.The book gave William an idea.There was a lot of wind in Wimbe.He would ...
The windmill has at least one and preferably three vaned wheels (220) rotating about vertical axes, connected mechanically to a generator (250). Each of the wheels has three vanes (230), each with a cross-section in the shape of an arc of a circle, made from a composition material and...