WangKungandWangWeiarebrothersandsisters.Theyhavedreamedof (56)___(take)agreatbiketrip.(57)___wasWangKunwhofirsthadtheidea(58)___cyclealongtheentireMekongRiver.TheyrodebicyclestotravelalongtheMekongRiver,thesouceof(59)___isinQinghaiProvince.(60)___itentersSoutheastAsia,ittravelsslowlythroughhillsandlowvalleysandtheplainswherericegrows.Despitethe(61)___(difficult),WangWeiandWangKunwere(62)___(determination)tobegintheirjourneyat(63)___altitudeofmorethan5,000metersinQinghaiProvince.Duringtheirjourney,theyexperiencedthecontinouschangeoftheweather.FinallytheyreachedDaliinYunnanProvince,(64)___DaoWeiandYuHangjoinedthem.The(65)___(happy)ofthemwentonwiththeirgreatbiketrip.