While many of the raised structures are connected by zip lines only, the community is continuing to develop a sky bridge that currently connects a smaller cluster of tree houses.

现在已经建好的大多数树屋都是用铁链连接在一起的，社区正在建设空中桥梁目前连接着一小群树屋。

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Now although sunlight indeed travels along straight lines, the projections of these lines onto the spherical sky are great circles.

虽然阳光呈直线照射，但光线在球型天空的投影却是巨大的圆形。

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Perched above the forest floor, these tree houses are connected by zip lines and sky Bridges, accessible by stairs and ladders from the ground level.

坐落在森林的地面之上的这些树上小屋用铁链和空中桥梁连接着，还有通到地面上的梯子。

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The team is planning all sorts of other capabilities for the tech, including navigation systems -- "Power lines are like highways in the sky, " says one of the researchers -- and auxiliary surveillance systems that power up when jacked in.

ENGADGET: Air Force developing UAVs that can recharge on power lines

An eye in the sky could be used to interdict drugs, size up needs in disaster relief, ensure port security, check power lines and fuel pipelines, fight forest fires and count wildlife, Brown said.

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