in the 是不是1990年到1999年都是算in the 1990s?

in the 是不是1990年到1999年都是算in the 1990s? in the 1990s'还是in the 1990's in 1990s还是in the 1990s in early 1990s还是in the early 1900s? from the 1990s in the 1990s的区别 in the 1990s 、 in 1991s 、 in the 1991s、 in 1990都有什么含义? in 1990 和 in the 1990s的区别 in the 1980s和in the 1980's是不是都对的? in the 1990s和in the 1990's的区别 The young people in the 1990s ______ jeans. The Internet appeared in the 1990s.(同义句转换) in the early 1990s和in the early 2000s分别是指多少年啊?