a fool's paradise字面意思傻瓜的伊甸园，引申为黄粱美梦。

【例句】
His uncle left him& 200 and John is living for the time in a fool's paradise.
约翰的叔叔留给他200英镑，他眼下正做着黄粱美梦。

She indeed lives in a fool's paradise as she always dreams about making a huge fortune overnight.
她总想顷刻间大发横财，的确有点想入非非。