Ⅰ. 根据首字母或汉语提示，用本单元所学的单词完成下列句子（每个1分，共10分）
1．China h_________ the 29th Olympic Games in 2008.
2．More than 10 000 a_________ took part in the Games.
3．Since you're not in good health, it's quite necessary for you to pay attention to p____________ exercise.
