buy a pig in a poke不是指“买袋子里的猪”，其正确的含义是看不清东西而瞎买；未见真货，不要瞎买。

【例句】
Purchasing a home without inspecting it first is like buying a pig in a poke.
购房不先验房，就是看不清东西而瞎买。

If you don't get a good look at the engine of a used car before you buy it, you'll wind up buying a pig in a poke.
如果在买车前不好好看看二手车的发动机，结果就是看不清东西而瞎买。