英文:Our flag is raised to the top of a pole by a rope and two pulley.
中文:我們的旗幟被用一根繩子和兩個滑輪升到了竿頂。
英文:A simple device, such as a lever, a pulley, or an inclined plane, that alters the magnitude or direction, or both, of an applied force; a simple machine.
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