at (1)表示在小地方; (2)表示“在……附近，旁边”
in (1)表示 在大地方; (2)表示“在…范围之内”。
on 表示毗邻，接壤
to 表示在……范围外，不强调是否接壤
He arrived at the station at ten.
He is sitting at the desk.
He arrived in Shanghai yesterday.
Jiangsu lies in the east of China.
Russia live on the north of China.
Fujian is to the south of Jiangsu Province.

at (1)表示在小地方; (2)表示“在……附近，旁边”
in (1)表示 在大地方; (2)表示“在…范围之内”。
on 表示毗邻，接壤
to 表示在……范围外，不强调是否接壤
He arrived at the station at ten.
He is sitting at the desk.
He arrived in Shanghai yesterday.
Jiangsu lies in the east of China.
Russia live on the north of China.
Fujian is to the south of Jiangsu Province.