But sixty years_____things were quite different填ago 还是before理由

But sixty years_____things were quite different填ago 还是before理由
But sixty years_____things were quite different
填ago 还是before
理由

But sixty years_____things were quite different填ago 还是before理由
ago 因为句子里的be动词是were她是are的过去式

ago

ago 用在时间段之后 before 用在时间点之前 例如 before 9 o'clock

理由
填ago是以前的意思