《黄河大合唱》是著名作曲家（）于（）年在（）创作的，是我国近代音乐史上一部具史诗性的大型声乐作品。

A. holding down the life preserver against the chest with one arm crossing the other，covering the mouth and nose with a hand，and feet together
B. knees bent and held close to the body with both arms around legs
C. body straight and arms held tightly at the sides for feet first entry into the water
D. both hands holding the life preserver below the chin，with knees bent，and legs crossed

A. 百分之百显示舞台上的所有对象
B. 百分之百显示舞台上的选定对象
C. 在工作区中，显示整个舞台
D. 移动舞台