It takes two days by foot or mule to get to the bottom of the Grand canyon and back, and at least two weeks to complete the journey through the canyon by raft.
它需要两天的步行或骡子到达大峡谷的底部和背部,用木筏至少两个星期才能完成穿越大峡谷的旅程。
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Then the response of the hull with floating raft system was analyzed when the bottom of hull was exerted by a vertical shock wave from an underwater explosion...