Inthesummerof1978anEnglishfarmerwasdrivinghistractorth...
问题详情： Inthesummerof1978anEnglishfarmerwasdrivinghistractorthroughafieldofwheatwhenhediscoveredthatsomeofhiswheatwaslyingflatontheground.Theflattened(变平的)wheatformedacircleaboutsixmetersacross.A...