Bon, vu qu'il s'agit de trois questions, je vais supposer que ton/ta prof veut qu'on y réponde.
In your country do businesspeople usually:
1-Have business breakfasts?
No. In my country, businessmen and businesswomen usually have business lunches.
2-Entertain businesspeople at home?
No, generally business people entertain their customers in bars or nightclubs.
3-entertain businesspeople at the weekend?
Businessmen and women generally entertain their customers during the week, but occasionally they may entertain them on weekends.