Look up, means research, go to a source looking for an answer. Look up the phrasal verb "look up" . Look over means review, skim, read quickly, peruse, consider quickly.

Do you mean metal rather than mental? The sentences are good

They are good but they are differents in meaning

She died a long time ago. He has been dead for a long time.

If I had been here，all I could have done was stop him.

Yes , but you can use her for a girl and his for a boy ,.

Assume or take on , and so one

Man is transgressor