- 問題詳情:Today,bicyclesareelegantlysimplemachinesthatarecommonaroundtheworld.Manypeopleridebicyclesforrecreation,whereasothersusethemasameansoftransportation.ThefirstbicyclewasinventedinGermanyin1818.Becauseitwasmadeofwood,itwasn’tverystrongnordidith...
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