一只小鸟看见高高的屋顶蹲着一只青蛙,好生奇怪:青蛙没有翅膀,它是怎样飞到屋顶的呢?“我不是飞到屋顶的,而是跳到屋顶的。”青蛙说。“跳到屋顶?这怎么可能呢!”小鸟感到不解。“是的,我无法一下跳到屋顶。”青蛙说,“但我可以从地面一下跳到窗台,再从窗台一下跳到阳台,又从阳台一下跳到屋檐,然后再从屋檐一下又一下跳到屋顶,就像你们小鸟飞翔一样,仅靠展开一次翅膀,是无法飞起来的,只有一次又一次搧动翅膀,才能 A bird saw a tall roof squatting a frog, so strange: frogs without wings, how is it flying to the roof? ”“ I do not fly to the roof, but to the roof. ”“ Frog Say. ”Jump to the roof? How is this possible! “ Bird puzzled. ”Yes, I can not jump to the roof. “ The frog said, ”But I can jump from the floor to the window sill, and then from the window sill to the balcony, and from the balcony to the eaves, and then from the eaves Another jump to the roof, just like your birds fly, just by opening a wing, it is impossible to fly, and only flapping their wings again and again in order to