Can you please check these short conversations? Thank you.

1.Doctors have to wash their hands and put their gloves on before operating on patients.
2.Safety guards make sure that no-one enters the hospital without permission.
3. He was operated on his knee. How do you call a waiter in a restaurant in your country if you want to sound polite?
4.What do you usually have for lunch? Do you have a starter and a main course as in Italy?
5.Are you ready to order? Yes, sure (?). Can I have a vegetarian pizza. Is it spicy? It’s with tomatoes, cheese, onions and corn.
6.To drink I’ll have an orange juice.

1 - OK

2 - "no one" (no hyphen)

3 - His knee was operated on.

To call a waiter, just raise your hand.

4 - "appetizer" rather than "starter"

5 and 6 - OK