备用

In a sentence

• 请将这些备用钥匙放在安全的地方。

  Please place these spare keys in a safe location.

  The word "备用" is used as an adjective here, meaning "spare" or "back-up," to describe the keys.

• 为了避免断电，请准备备用电源。

  To avoid losing power, please prepare a backup power source.

  "备用" functions as an adjective meaning "backup" or "reserved," applied to the power source.

• 我们需要准备一份备用计划，以应对意外情况。

  We need to prepare a contingency plan to handle unexpected situations.

  Here, "备用" describes the plan as being prepared and kept as a contingency or alternative.