无空不钻wú kòng bù zuān

avail oneself of every loophole; exploit every advantage; slip into every opening/“这要小心提防呀，酸辣汤那个坏蛋，”陶阿毛指着梅厂长的汽车刚开走的方向，说“是～的……”(周而复《上海的早晨》Ⅰ—521) “That’s a point we shall have to watch carefully,then. That skunk ‘Pepper-and Vinegar Soup’，” (Tao Amao pointed in the direction in which Mei Zuoxian’s car had gone) “is as crafty as they come. …”