The 2007 FIVB Beach Volleyball Women's Challenger will open on Aug.13. Altogether 24 teams  from 13 countries and regions will participate.On noon Aug.12,a pair from China and a pair  from USA had done pre-match training for an hour at Chaoyang Park Beach Volleyball Ground.Picture shows Chinese players Yue Yuan and Zhang Wenwen and American  players Rosalinda Masler and Kealani Sierra Kimball training together.