Here are some examples:
* Estou preocupado com o meu filho. (I am worried about my son.)
* Ele está preocupado com o futuro. (He is concerned about the future.)
* Ela parecia preocupada com a notícia. (She seemed worried about the news.)
It's important to note that "preocupado" can also mean occupied or busy, but this usage is less common.