You're totally right, I was confusing modifiers with Chinese's general looseness towards word class, a tendency even more pronounced in Classical Chinese [1]. T

You're totally right, I was confusing modifiers with Chinese's general looseness towards word class, a tendency even more pronounced in Classical Chinese [1]. That means what looks like modifier/preposition could be functioning as a verb instead. So my mother-in-law just said '上海不在海上', i.e. 海上 is closer to the literal meaning of 'on top of the ocean (physically)', which the city is not. Perhaps 上 here acts as a verb or gerund ((going up / on the way) to the ocean)? 下海 means 'going (down) to the ocean'. The rabbit hole here can get deep (and thanks for drawing me in!), this book [2] goes in-depth about how word class and word order influenced one another as Chinese developed. [1] https://en.wikipedia.org/wiki/Classical_Chinese_grammar#Word_class_flexibility https://en.wikipedia.org/wiki/Classical_Chinese_grammar#Word... [2] https://www.google.com/books/edition/_/r9WO6g5mqi8C?hl=en&gbpv=1&pg=PR10&dq=grammaticalization+chinese https://www.google.com/books/edition/_/r9WO6g5mqi8C?hl=en&gb...