源头

Relating to natural resources, such as solar energy or wind power, that are not depleted when used. It describes materials or energy sources that can be replaced naturally.

Very serious, stern, or severe. It is typically used to describe situations, challenges, or tests that are difficult to handle.

To use up or spend a lot of resources, such as time, money, or energy, often in a way that suggests a significant amount is required.

The process of eroding or being eroded by natural agents; or the gradual destruction/diminution of something like rights or value.

To make something continue in the same way or at the same level as before. It often refers to order, living standards, or physical states.

Sources of power, such as fuel or electricity, used to provide light and heat or to work machines.

To cause physical harm to something so as to impair its value or usefulness; or to cause injury to someone's health or reputation.

The system of vehicles and pedestrians moving along roads or through the air; transportation. It frequently appears in discussions about urban planning and pollution.

The introduction of harmful materials into the environment, such as air, water, or soil. It is a high-frequency topic in academic tests.

To use up resources, energy, or time. In academic writing, it often refers to the consumption of natural resources or the energy expenditure of a system.