Odpowiedź:
1 Last year my friend invited me to his birthday party.
It was a very hot day. There was plenty of delicious food on the party. I ate a lot. I didn't feel very well and I had a stomach ache. I called my dad and he took me home.
2 First, to open air music event can come more people. It's no limit, because it isn't in a building.
Such an event can be organized in a lot of places. There aren't concert halls in every town or city, and especially in the country, so it's available for more people.
It's safer in cause of the fire.
It's open air, so if there are plenty of fans, they won't feel weak like in a building where can be hot and stuffy.