base 侧重指构成或支撑某一具体物体的基础，也可指军事基地或用作比喻意义。
basis 主要用作抽象或引申意义。
foundation 用于具体意义时，侧重指坚固结实的建筑物的基础或地基；用作比喻意义时，与basis基本相同。
ground 含义与basis和foundation接近。一般指某种决定、论点或关系的基础，也可指某种原因的基础。
参考例句
1. They love the house, but are not sure of the firmness of its foundation. 他们很喜欢这个房子，可是对房子地基的坚固性没有把握。
2. They loved the house, but were not sure of the firmness of its foundation. 他们很喜欢这个房子，可是对房子地基的坚固性没有把握。
3. The corpus constitutes the common ontology foundation of ethics and worth. 主体性构成了伦理与价值共同的本体论基础。
英英解释
n.
1. the basis on which something is grounded
2. an institution supported by an endowment
3. the fundamental assumptions from which something is begun or developed or calculated or explained
4. lowest support of a structure
5. education or instruction in the fundamentals of a field of knowledge
6. a woman's undergarment worn to give shape to the contours of the body
7. the act of starting something for the first time; introducing something new
