（辨析主题句）Read the following paragraph and underline the topic sentence.

Many people think that a nurse is a smiling woman, in a white uniform and cap, whose main jobs are to take your temperature and give you injections while you are in hospital. However, this stereotype of a nurse is not correct. Today’s nurses, both male and female, are trained professionals who offer comfort and assistance to people who are physically or mentally ill. They work in hospital bedrooms and operating room; they also help people in institutions and provide professional home care. Using their medical and psychological training, they take care of their patients and help them recover from illnesses. A good nurse also teaches his or her patients how to stay healthy.