never have I seen him before 这个对
倒装句
陈述句是I have never seen him before.我以前从没见过他
never 和before 不是词组,连用没有任何意义,也不符合语法习惯
never before has china developed rapidly?
个人认为,这个before 跟第一句的语法成分不一样
陈述句应该是china has never developed so rapidly as before
倒装之后 应是 never as before has china developed so rapidly!
so……as 在口语中省略了
多读读就能分辨出来了