阅读理解Passengerpigeons(旅鸽)onceflewovermuchoftheUnitedStat...
问题详情：阅读理解Passengerpigeons(旅鸽)onceflewovermuchoftheUnitedStatesinunbelievablenumbers.Writtenaccountsfromthe18thand19thcenturiesdescribedflocks(群)solargethattheydarkenedtheskyforhours.Itwascal...