D) There is a angle between optic axis and crysta face 光轴与晶体表面有一夹角(斜入射) 光轴 光轴 晶体 e光o光 e光 晶体 光轴 光轴 D) There is a angle between optic axis and crystal surface 光轴与晶体表面有一夹角（斜入射）