Numerous ideas were submitted for the project, including concepts ranging from rolling eggs to tilting tanks, from giant seesaws to overhead monorails.
许多人为该项目提供了想法，包括从滚动的鸡蛋到倾斜的坦克，从巨大的跷跷板到空中单轨铁路等概念。
their seesaws always went up,but they never came down.
他们的跷跷板总是起来，但是从不下去。
Their seesaws always went up, but they never came down.
