在coast,river等詞前面表示"(坐落) 在…上; 在…旁"時(shí)用on.

on的具體用法總結(jié)如下：
(表示接觸、支撐) 在…上
例：He is sitting beside her on the sofa.他正挨著她坐在沙發(fā)上.
例：On top of the cupboards are straw baskets.櫥柜頂上是幾個(gè)草籃子.

(表示粘貼、附著) 在…上
例：I stared at the peeling paint on the ceiling.我盯著天花板上剝落的油漆.
例：The clock on the wall showed one minute to twelve.墻上的鐘顯示11：59.

在…上
a glass on the desk
課桌上的一只玻璃杯
I know how to sew a button on.我知道怎么縫上扣子.

(表示方向) 到…上
例：He got his winter jacket from the closet and dropped it on the sofa.他從衣柜里拿出冬天的夾克,把它扔到沙發(fā)上.

倚在 (身體某部位) 之上
例：He raised himself on his elbows, squinting into the sun.他用雙肘撐起身體,瞇起眼睛看著太陽(yáng).

(表情) 在 (臉) 上
例：The maid looked at him, a nervous smile on her face.侍女看著他,臉上帶著緊張的微笑.

(穿) 上; (戴) 上
例：He put his coat on while she opened the front door.她打開(kāi)前門(mén)時(shí),他穿上了他的外套

帶在…身上
例：I didn't have any money on me.我身上一點(diǎn)兒錢(qián)也沒(méi)帶.

(視線) 在…上
例：Everyone's eyes were fixed on him.大家的目光都鎖定在他身上.

(身體某部位碰撞) 到某物上
例：Mr. Pendle hit his head on a wall as he fell.彭德?tīng)栂壬さ箷r(shí),頭撞到了墻上.
(坐落) 在…上; 在…旁
例：The hotel is on the coast.那家賓館在海邊.

在 (交通工具) 上
例：We waited till twelve and we finally got on the plane.我們一直等到12點(diǎn),終于登上了飛機(jī).

(登) 上
例：He showed his ticket to the conductor and got on.他向乘務(wù)員出示了車(chē)票,就上了車(chē).