concentrate on one thing only;have a one-track mind ❍ 它将引导人们思想衰退，～，见不得世面，唱不得对台戏。(《毛泽东选集》Ⅴ—346) It will lead to mental deterioration,one-track minds,and unpreparedness to face the world and meet chal lenges.
单打一dan da yi
❶concentrate on one thing alone ❷have a one-track mind