tread on delicate ground

• 触及微妙的问题,碰到棘手问题,小心翼翼

tread on delicate ground的用法和样例：

例句

1. Cautiously, Lill knocked on her very first door.
   莉尔小心翼翼地敲了敲她看到的第一扇门。
2. He set it down carefully on the baize cloth.
   他小心翼翼地把它放在粗呢桌布上。
3. Social workers operate on the razor's edge.
   社会工作者工作时如履薄冰。
4. OPEC is still skating on thin ice.
   要达到这样一些目标，欧佩克依然如履薄冰。