怎样分清楚

at 在
1. I met him at the bus stop.
我在公共汽车站遇到他的。
2. We can see the stars at night.
夜晚我们可以看见星群。
3. I usually get up at 8 o'clock.
我通常8点起床。

in 在……里面
1. I'm afraid we're in for a storm.
恐怕我们要遇上暴风雨了。
2. We sail on the lake in summer.
夏天我们在湖上泛舟.
3. He lost his way in the forest.
他在森林中迷路了。

on在……上面
1. He went on with his work.
他继续他的工作。
2. We sail on the lake in summer.
夏天我们在湖上泛舟.
3. 81 Can I stop over on the way?
我在中途可以停吗？

for为了……
1. He shook his head, for he thought differently.
他摇摇头，因为他的想法与此不同。
2. This coat is too small for me.
这件上衣对我来说太小了。
3. It's too early for getting up.
现在起床还太早。

of…的,表示所属
1. Many of the students came from other countries.
学生中许多人来自其他国家。
2. 53 We are happy to be of help.
我们十分乐意帮助。
3. Doubt is the key of knowledge.
怀疑是知识之钥。

说实话，分清楚这些需要自己多看几个例