I need some help for my homework: I'm not sure about this sentences please fix the pronoun clarity and agreement error. (When I went to the car

I need some help for my homework: I'm not sure about this sentences

please fix the pronoun clarity and agreement error. (When I went to the car dealership, they told me my warranty would cover everything. ) (The nurse said that I should replace my mercury thermometer because they can be a hazard if it breaks.)