Choose the correct words

1. By working at the lab, she gained some [practical|realistic] skills.
2. It's better to spend more and buy [never-ending|long-lasting] batteries that work more hours.
3. Stella is very committed to [reaching|managing] her goals.
4. All his years of experimentation [achieved|contributed] to the final successful invention.
5. Exhausted from working all day, Karen immediately [fell|dropped] into a [heavy|deep] sleep.
6. Why don't you sleep [over|on] it and we will discuss it again in the morning.