各位高手们 请告诉我 八十年代后期 用英文怎么说

in the late 1980s 这样说就可以了。

In the late 1980s.

1980s 指的就是20世纪80年代

类似的有

we were poor in 1990s, but now, everything is different.

这是一个很简单的时间表示方法，一看就会用。

in the late 1980's/1980s

in the late 80s(eighties).