这些形容词均有“基本的，基础的”之意。
basic : 普通用词，指明确、具体的基础或起点。
- I really need to get some basic financial advice.
我的确需要一些基础的金融方面的建议。 - He only has a basic command of English (= he only knows the most important and simple words and expressions).
他只会说很基本的英语。 - The basic (= most important) problem is that they don't talk to each other enough.
根本问题在于他们彼此不怎么说话。 - It's the most basic model (= it only has the most simple features).
它只是个最基本的模型。 - The crisis has led to price rises in basic foodstuffs, such as meat, cheese, and sugar.
危机导致了肉、奶酪、糖等基本食品价格的上涨。
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。
- Government support will be essential if the project is to succeed.
这个项目能否成功，政府的支持至关重要。 - There is essential work to be done before the building can be re-occupied.
这座楼在重新入住前必须进行必要的维修。 - Water is essential for/to living things.
水对于生物来说是必不可少的。 - It is essential (that) our prices remain competitive.
我们保持价格方面的竞争优势是至关重要的。 - For the experiment to be valid, it is essential to record the data accurately.
要保证实验的有效性，就必须精确地记录数据。
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。
- We need to make fundamental changes to the way in which we treat our environment.
我们需要从根本上改变对待环境的态度。 - It's one of the fundamental differences between men and women.
这是男女之间的基本差别之一。 - The school is based on the fundamental principle that all children should reach their full potential.
这所学校的基本原则是充分发挥每个孩子的最大潜力。 - Diversity is of fundamental importance to all ecosystems and all economies.
多样性对所有的生态系统和经济结构都极为重要。
radical : 着重指事物的根本或其来源。
- We need to make some radical changes to our operating procedures.
我们需要对操作规程进行一些根本性的变革。 - I'm just having my hair trimmed - nothing radical.
我正把头发剪短一下——没什么大改变。
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。
- A strong opposition is vital to a healthy democracy.
有一个强大的反对党对于健康的民主制度来说非常重要。 - She had found out some information of vital importance.
她已经查出了一些极为重要的信息。 - The kidney plays a vital role/part in the removal of waste products from the blood.
肾脏对于排除血液中的废物起着至关重要的作用。 - It's absolutely vital that you do exactly as I say.
完完全全按我说的去做，这至关重要。 - It is vital to get medical supplies to the area as soon as possible.
要尽快把药品送往该地区，这至关重要。
