basic、essential、fundamental、radical与vital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。