Second, since the radius vectors r to the extreme points of the ellipse satisfy(5. 3-12)they are parallel to the two allowed D vectors.是什么意思_Second, since the radius vectors r to the extreme points of the ellipse satisfy(5. 3-12)they are parallel to the two allowed D vectors.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句