Here are some synonyms for "pensively":
* Thoughtfully
* Reflectively
* Contemplatively
* Musingly
* Meditatively
Here are some examples of how to use "pensively" in a sentence:
* She sat by the window, pensively watching the rain fall.
* He stood pensively at the edge of the cliff, gazing out at the vast ocean.
* The old man sat pensively in his rocking chair, remembering his youth.