pig in a poke
以与实际情况不符的方式出售或购买商品，即没有检查也没有了解就购买商品
口语·警示盲目购买
英文释义
to buy or accept something without knowing its true nature or value
例句
Buying that used car without a test drive was like buying a pig in a poke.
典故来源
源自中世纪欧洲市场，骗子将猫冒充猪装在袋子里出售，买家未检查就买下。