Answer:
1. the hotel rooms are all cleaned by the staff.
2. in Brazil, Portuguese is spoken by the people.
3. the company website is updated frequently.
4. this is the most beautiful beach seen by the people.
5. the products are shipped by somebody via express mail.
6. this sweater is given to me by a friend.
7. these letters are written by a famous author.
8. the award was chosen by the teacher for her to receive.
9. all of us were woken up by a knock on a door.
10. the college entrance exam was taken by over 300,000 students.
Explanation:
To change a sentence from active to passive voice, do the following:
Move the active sentence's direct object into the sentence's subject slot.
Place the active sentence's subject into a phrase beginning with the preposition by.
Add a form of the auxiliary verb be to the main verb and change the main verb's form.
hope it helps
please correct me if I'm wrong