n.[U][(+of)]

1. 保存
2. （对自然资源的）保护，管理
   Conservation is one way to make sure we have enough energy in the future.

   对自然资源的保护是保证我们将来有足够的能源的一种办法。

3. 【物】守恒，不灭
   conservation of mass

   质量守恒

n.

1. preservation or restoration of the natural environment and wildlife.
   ▸preservation and repair of archaeological, historical, and cultural sites and artefacts.
2. careful use of a resource.
3. Physics  the principle by which the total value of a quantity remains constant in a system which is not subject to external influence.