身份证

In a sentence

• 我必须带上身份证去银行办理业务。

  I must bring my ID card to the bank to conduct business.

  In this sentence, 身份证 denotes the form of identification necessary for completing official transactions, emphasizing its practical usage.

• 丢失了身份证需要马上补办。

  If you lose your ID card, you need to reissue it immediately.

  Here, 身份证 is referred to as a document that, if lost, needs replacement, highlighting its importance.

• 进入考场时，考生必须出示有效的身份证。

  Examinees must present a valid ID card to enter the examination hall.

  This sentence uses 身份证 to mean a required proof of identity for entry into specific locations or events, showcasing regulatory requirements.