Manypeopleenjoytakingtripsbythemselves.Unluckily,theydo...
问题详情：Manypeopleenjoytakingtripsbythemselves.Unluckily,theydonotalwayshavethebest____21____ead,peopleshouldconsidergrouptours.Takingagrouptourisawisechoiceforpeopleto____22____themselves.First,group...