"Reserves the right to"、"have the right to"、"be entitled to"、"have the power to" 和 "have the authority to" 都可以用来表达某人或某实体具有某种权利或权限，但它们在语气、上下文和具体含义上有所区别：

Reserves the right to：to keep back a right for oneself to engage in a particular action or decision, often used in legal, contractual, or formal settings to indicate that a party may choose to exercise this right at a future time under certain conditions.

这个表达通常用于法律文本、合同或声明中，强调某方在将来可能行使的特定权利，但并未立即行使。它暗示了一种慎重的保留态度，可能在特定条件下才会行使该权利。

如The company reserves the right to modify the terms of this agreement at any time.

Have the right to：to possess a justified claim or entitlement to carry out a specific action, make a decision, or enjoy a particular benefit, based on legal, moral, or ethical grounds. It implies a recognized or established authority to do something without needing additional permission.

这是一个更直接的表达，强调某人或某实体按照法律、规则或协议具有的明确权利。它通常用于强调现有的、无需额外条件即可行使的权利。

如Citizens have the right to free speech under the constitution.

Be entitled to：to legitimately possess a certain right or claim to something, such as a service, benefit, or consideration, based on legal, regulatory, or agreed-upon standards or qualifications. It often implies a right derived from one's status, position, or agreed terms.

这个表达侧重于某人或某实体因为特定的资格、条件或法律规定而应得到的权利或利益。它通常用于强调应得的权益或待遇。

如：Employees are entitled to a safe working environment.

Have the power to：to possess the capability, means, or authority to perform an action or enact a decision, especially one that affects others. This can involve the ability to influence, control, or direct outcomes, often vested in a position of authority or through legal mandate.

这个表达强调某人或某实体有执行某些行动或作出决定的能力或权限，通常涉及对他人或情况产生直接影响的能力。

如The president has the power to veto legislation.

Have the authority to：to have the official or legal power to act, make decisions, or enforce rules and regulations. This involves a formal or legal delegation of power, typically associated with a position in an organization, government, or institution, granting the holder the legitimacy to carry out specific actions or duties.

这个表达强调某人或某实体根据其职位、角色或法律规定具有的正式或法定的权限，通常用于强调基于官方或法律授权的行动。

如：The regulatory agency has the authority to enforce compliance with the laws.

总的来说，这些表达虽然都涉及“有权”的概念，但"reserves the right to"更多强调未来可能行使的保留权利；"have the right to"和"be entitled to"侧重于现有的、应当享有的权利；而"have the power to"和"have the authority to"则强调执行某些行动的能力或正式权限。