the party concerned

基本解释

A: The security guard involved in the case is employed by the party concerned to ensure the security of the apartment.
答：此次事件涉及的保安人员是有关方面为维护公寓安全而雇佣的。
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Personnel who has an interest in the party concerned, which may affect the impartiality of the appraisement, shall withdraw.
凡与当事人有利害关系，可能影响公正鉴定的人员，应当回避。
Where the party concerned provides corresponding lawful proof or makes up corresponding formalities, the motor vehicle shall be returned in time.
当事人提供相应的合法证明或者补办相应手续的，应当及时退还机动车。

House Democrats have made some progress in recent days in bridging differences between liberal lawmakers focused on covering the uninsured and more conservative party members concerned about the cost of the reform effort.

In particular, the party is concerned to nip disparate sites of dissatisfaction in the bud before they blossom.
ECONOMIST: Protests in Tiananmen Square

当事人
From the prescription of the Tang Dynasty we can find the tern that need to have:first ,the party concerned’s behavior broke the law.
从唐律的规定中可看出需具备的条件有：首先，当事人实施了违法行为。