I'm not sure if there are some rules about "над" and "надо", but we always use "над" when it followed by a vowel. And we use "надо" when there are too many consonants one after another, like "надо мной". If you say "над мной" it's normal, but it sounds a little bit clumsy. And what about "мной, мною" - "мною" is slightly fusty and it is usually used in poetry. There are some examples: над пропастью [во ржи], [как фанера] над Парижем :) надо мной, надо лбом. Кавказ подо мною, между мною и тобою, не уходи, побудь со мною

Hi Mario. Preposition над (надо) is used with дательный падеж. I am sure you know this. this preposition has several meanings: 1. over and above. Над городом летал воздушный шар Ковер висел над диваном 2. when we want to emphasize someone's priority, his higher level- его сделали старшим над всеми 3. when we want to say that someone was focused on something. Вчера я трудился над задачей With regards to надо , it was used with мной and the nouns, which begin with letters р and л have two consonants - надо ртом, надо рвом. Надо мною тишина As for мною и мной . Both are possible. The second one is more formal. надо мною лист кружится надо мной смеются I hope it helps

Небо надо мной так красиво -- The sky above me is so beautiful. Над долиной парят орлы -- There are eagles soaring over the valley. Надо is generally used if the next word starts with two or more consonants, but it is not a regular rule; e.g. "The Catcher in the Rye" -- "Над пропастью во ржи" Мною is mainly used in poetic language.