向量分析[诊断]法

A. complete the stroke，raise your oar slightly，swinging the oar slightly forward，and place it in the boat
B. lift the oar in a vertical position
C. complete the stroke and hold the oar out of the water
D. dip the blade of your oar into the water vertically and hold it perpendicular to the keel line

A. 正确
B. 错误

A. 平流层
B. 热层
C. 外层