不可或缺

Not direct; occurring through an intermediary or as a secondary result.

Positive or favorable; also refers to the front side of an object.

Thorough, profound, or in-depth; usually describing an analysis, understanding, or explanation that covers all aspects clearly.

To divide or partition something into distinct sections or categories according to a certain standard.

To state something again clearly and strongly to emphasize its importance or to ensure it is understood.

To borrow and read books or other materials, usually from a library.

Generally recognized or universally accepted as being true, valid, or of a certain quality by the public or a specific group.

The state of being limited or having restrictions; the qualities that prevent someone or something from being as effective as they could be.

A comparison between two things that are similar in some way, often used to explain a complex idea by comparing it to something simpler.

And then; after that; a step further; used to show progress in action or development.