several hundred 中的hundred 后要加s

several hundred 中的hundred 后要加s several hundred several hundred后面的名词要加s吗 hundred It's several hundred years old.(同义句替换) It __ __ several hund 为什么 two hundred hundred不用加s? hundred后面加s live for several hundred years 等于什么 several后面加hundred 和million 是咋变 在哪加s 加了of呢 辨析一下several hundred 和several hundreds of several hundred 和several hundreds of有什么区别? several hundred,several hundreds,sebveral hundredsof 哪一个正确?