" To know something inside out" . It's very similar. I talked about the T-shirt.

Know something inside out。这个短语非常相似。我拿 T 恤举例。

So, if you know something inside out, then you know it really well, right?

如果你对某件事了如指掌，那你就非常了解它。

" Go into business" , " set up a restaurant" , " know something back-to-front" , " know something inside out" , " a seasoned worker" , " be on the ball" , " take someone on" , " spread the word" .

“经商”、“开饭馆”、“了如指掌”、“洞悉透彻”、“经验丰富的工人”、“随机应变”、“录用某人”、“散布消息”。