basic 普通用词，指明确、具体的基础或起点。
essential 语气比basic和fundamental强，强调必不可少，暗含某物如缺少某部分，则失去本质特征的意味。
fundamental 书面用词，不如basic使用广泛，侧重指作为基础、根本的抽象的事物。
radical 着重指事物的根本或其来源。
vital 正式用词，侧重指维持生命、活力必不可少的，或生死攸关的。
参考例句
1. Family is the basic unit of society. 家庭是社会的基本组成部分。
2. Why are cells the basic units of life? 为什么细胞是生物体的基本单位?
3. Master Basic Strategy with our advanced Drill and Table modes. 主人基本战略我们先进的钻机及表模式。
英英解释
n.
1. a popular programming language that is relatively easy to learn; an acronym for beginner's all-purpo
2. (usually plural) a necessary commodity for which demand is constant adj.
1. pertaining to or constituting a base or basis
2. reduced to the simplest and most significant form possible without loss of generality
3. serving as a base or starting point
4. of or denoting or of the nature of or containing a base
