black core

例句：

1. 1. The company's black core is revealed in the annual report.
   公司在年度报告中揭露了其黑幕。
2. 2. The investigation found a deep-seated black core of corruption within the organization.
   调查发现该组织内部存在根深蒂固的腐败问题。
3. 3.The government has been accused of having a black core of officials who are corrupt and nepotistic.
   政府被指控拥有一群腐败和裙带关系的官员。