my answer

送交者: newbigman 2013月06月12日14:25:29 于 [灵机一动] 发送悄悄话

回  答: 漂流物和水速 由 gugeren 于 2013-06-12 12:52:49

1. does not matter what is the speed of the boat--as long as it's bigger than 1.

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The reason? - gugeren 06/12/13 (742) 　　　　as inside - newbigman 06/12/13 (958)

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