in 1980/in 1980s / in the 1980 / in the 1980s / in the 1980's/in the 1980'
问题描述：
in 1980/in 1980s / in the 1980 / in the 1980s / in the 1980's/in the 1980'
答
in 1980 在1980年,
eg:I was only 20 in 1980.
1980年的时候我才20岁.
in the 1980s=in the 1980's
在20世纪80年代,意为在1980~1989这十年间.
eg:The song is popular with the young in the 1980s.
20世纪八十年代时这首歌在年轻人中很流行.
其余的形式没有见过.