Ответы и объяснения

Ответ на первый вопрос - это второе предложение в тексте.
1) The first Olympic Games took place in 776 B.C.
2) The  Olympic Games took place every four years.
3) At first, the athletes took part  only in race (the sprint). можно ответить и по-своему. 
The first competitions were racing (sprinting).
4) The Byzantine Empreror Theodosius abolished the Olympic Games.
5) The first modern Olympic Games were held in Athens, Greece in 1896.
6) спишите 4-й абзац первое предложение
7) 5-й абзац второе предложение
8) Athletis from Greece march the first around the stadium in the parade of Nations 
9) Athletis light the Olympic  Flame.