a bond轴向键aart.一(个)；每一(个)；任一(个)n.英语字母表的第一个字母；学业成绩得优者；表示“最好”的符号Aortic valve incompetence主动脉瓣关闭不全a joyful state of affairs事情的欢欣鼓舞的状态a genus of Polynemidae.多指马鲅科的一个属。a triple balance of power三足鼎立a plume of smoke/steam一缕烟[蒸汽a cold drab little office冷冰冰的小办公室a facile style of writing流畅的文体a sheet of glass/steel一块玻璃；一张钢板a drive-time radio show交通高峰驾车时间的广播节目A ground for legal action诉因法律诉讼的根据