1. 基本的;根本的;主要的;基础的
    You use fundamental to describe things, activities, and principles that are very important or essential. They affect the basic nature of other things or are the most important element upon which other things depend.

fundamental的解释

    e.g. Our constitution embodies all the fundamental principles of democracy...
           我们的宪法体现了民主的所有基本原则。
    e.g. A fundamental human right is being withheld from these people...
           这些人被剥夺了一项最基本的人权。

2. 根本性的;固有的;根深蒂固的
    You use fundamental to describe something which exists at a deep and basic level, and is therefore likely to continue.

    e.g. But on this question, the two leaders have very fundamental differences...
           但在这个问题上，两位领导人有着根本性的分歧。
    e.g. Amnesty says there are fundamental flaws in their military justice system.
           国际特赦组织称他们的军事司法体系存在着根本性的缺陷。

3. 必需的;不可或缺的
    If one thing is fundamental to another, it is absolutely necessary to it, and the second thing cannot exist, succeed, or be imagined without it.

    e.g. He believes better relations with China are fundamental to the well-being of the area...
           他相信和中国建立更加良好的关系对这一地区的繁荣发展至关重要。
    e.g. The method they pioneered remains fundamental to research into the behaviour of nerve cells.
           他们首创的方法在神经细胞活动的研究中一直是不可或缺的。

4. 最根本的;最重要的
    You can use fundamental to show that you are referring to what you consider to be the most important aspect of a situation, and that you are not concerned with less important details.

    e.g. The fundamental problem lies in their inability to distinguish between reality and invention...
           最根本的问题在于他们无法分清现实和虚构。
    e.g. It was not simply a practical matter, but a fundamental question of principle.
           那不仅仅是个实际问题，更是一个根本性的原则问题。

5. (研究)基础性的
    Fundamental research into a subject is concerned with gaining knowledge about the subject itself, rather than its practical aspects.

    e.g. Industry leaders want scientists to engage in fundamental research, not applied research.
           行业领袖希望科学家从事基础性研究，而非应用性研究。