CORNERSTONE
1. 英英释义：the basic part of something, on which everything depends
例句：Trust, commitment, and mutual respect are cornerstones of marriage.
2. 为什么选这个词？
“cornerstone”本意是建筑中的“基石”，和中文的“基石”一样，cornerstone 常被用作比喻事情的基础。当我们想表示“the fundamental/basic part of something”的时候，就可以用到更形象简洁的 cornerstone。
婚姻的基础是什么呢？许多人可能会说是信任、爱和互相尊重，这时我们就可以说： Trust, love, and mutual respect are cornerstones of marriage.
我们常说“Honesty is the best policy”，其实说的也就是诚实的重要性，我们可以用 cornerstone 把它改写为： Honesty is the cornerstone of all success, without which nothing would last.
《经济学人》在一篇特别报道中讨论了“开会”，第一段是这样写的：What do corporate leaders doall day? Much of their time is spent in meetings. No wonder: meetings are,among other things, the cornerstone of teams, which in turn are the basic building blocks of corporate existence.
这段话说明了会议的重要性，同时我们也可以学到 cornerstone 的一个同义表达 “building block”，它的本意是“积木”，也常被用来表示“基础材料”。
除了 building block，和 cornerstone 类似的常见表达还有 foundation, bedrock等，掌握了 cornerstone 后可以查一查这些同义词的用法。
个人拓展：
正式cornerstone：formal
In most countries, the family unit is still the cornerstone of society.
/building block: a basic element or component
/bedrock: the very basis; the foundation: Ownership of land is the bedrock of democracy.
/foundation: the basis or groundwork of anything: the moral foundation of both society and religion ；（化妆品）粉底
背诵：
同义词：cornerstone, building block, foundation, bedrock
Meetings are, among other things, the cornerstone of teams, which in turn are the basic building blocks of corporate existence.
Honesty is the best policy.
Freedom of choice is the cornerstone of democracy.
