on後面加什麼?

例句：

We were on a hill, right on the edge of town.

我們在一座小山上，正好位於城鎮邊緣。

What's on TV?

電視上有什麼節目？

Two men riding on motorcycles opened fire on him.

兩個騎在摩托車上的人向他開了槍。

His eyes lingered on the diamond ring on her finger.

他的'目光滯留在她手指上的鑽戒上。

I'm forever on a diet, since I put on weight easily.

我一直在節食，因爲我的體重很容易增加。