Vaccines in the Past
Vaccines are medicines that teach a person's body how to stop a disease in the future. Smallpox is a disease that killed millions of people. the past, doctors in Asia and Africa put smallpox scabs up a healthy person's nose to give them a weak smallpox disease. This worked as a vaccine on some people, but it killed others! In 1796, a British doctor called Edward Jenner made smallpox vaccines from cowpox - a disease that cows had. His vaccine stopped thousands of people dying from smallpox.
Нужно поменять врем past simpl на Present simpl и наоборот , если past perfect на present perfect и наоборот

Учебниккнига    1   01.04.2020 15:42    16