邯郸学步han dan xue bu
learning the Handan walk—try to acquire a new trick but lose the ability one already has
邯郸学步学步邯郸hán dān xué bù
邯郸：指战国时期赵国的都城；学步：学习走路。现多比喻模仿别人不到位，连自己本来就会的东西也忘掉了。imitate sb. in certain particulars, take a leaf out of another person’s book