Question

three years ago 和three years before在句子里有什么区别？怎么用？

three years ago 和three years before在句子里有什么区别？怎么用？如果有区别，请举几个例子。

Answer 1

ago是以现在为起点的以前，three
years
ago三年前，是相对于现在说的，时间用过去时。I
studied
in
the
school
three
years
ago.before是已过去某个时间为起点的以前，three
years
before相对于过去的某个时间的三年前，这种时间状语多见于间接引语，时态用过去完成时。He
said
that
he
had
studied
in
the
school
three
years
before.