Помогите пожалуйста упр 4

1 Vitamin С was discovered in 1747.

2 Toothbrushes were invented by the Chinese.

3 The people weren't taken to hospital after the accident.

4 A new medical centre was opened in my town last year.

5 A lot of remedies are made from plants.

6 I wasn't given any medicine at the hospital.

7 My teeth are checked twice a year.

8 Vaccinations weren't developed until the 18th century.

9 I called for an ambulance but it wasn't needed.