Bonjour à tous je n'arrive pas à faire cette exercice merci :

Corrige les phrases suivantes
en les réécrivant à la forme négative.

a. People celebrated Heritage Day before
1995.

b. South Africa became independent in 1994

c. In the 20th century, Robben Island was a museum.

d. In the 1960s, resistance movements began
in Pretoria.

e. A few years ago, people had a braai
on Heritage Day​