On the table she found a piece of paper________some puzzling secret codes.

供参考
on the table 这个人介词短语放在前面
便是这里所指倒装
原句可写成
she found on the table a piece of paper________some puzzling secret codes.\x14
或
she found a piece of paper________some puzzling secret codes on the table.\x14
至于为何是 C
原因
(1) 这个 relative clause 要有 on
即是 some puzzling secret codes were written on ...
所以 A 和 B 是错的
(2) 英语一般的用法是 that 作为 relative pronoun 时不跟 介词
而这也是 which 和 that 作为 relative pronoun 时的不同用法那这里的on that 改成 where 应该也可以吧？真对不起上文的倒装我答错了由於你的追问再细看一次发现漏看了其实倒装之处在於句子的後段即 on which were written some puzzling secret codes在这个子句( relative clause) 之中主语是some puzzling secret codes而它却跟在 动词 were written 之後所以便构成了倒装至於 where 的追问我会避免这样用where 一般的用法是指‘地方’其次会用於 指' situation' (某状况)或是用於比较你所指的 用 where 来代替 on that原句便变成... a piece of paper where were written some ...这样的句子我会接受亦可以理解其意思但我不会这样用最後让我再次说对不起