basis的基本意思是指人们采取某一行动的“原因；缘由”，也可指人们组织、安排和操作某事的“基准；准则；方式”，作此二解时basis是单数名词。basis还可指事物的“主要成分，最重要的部分”，由此事物得以形成、开始和发展，作此解时basis是可数名词，常用于单数形式，有时也用作不可数名词。

The rumour had no basis.那个谣言没有根据。
The belief has no scientific basis whatever.这个信念没有任何科学根据。
We judge a worker on the basis of his performance. 我们根据工作表现评价工人。
We run the meals-on-wheels service on a voluntary basis. 我们根据自愿的原则，开展上门送饭的服务。
They have arranged food imports on a barter basis.他们以易货贸易的方式安排食品进口。
The school is now on a firm basis.该校现在根基牢固。
▲～+prep.-phrase
There is no basis for this belief. 这种信仰是毫无根据的。
Nothing can shake the basis for my belief.什么也动摇不了我信念的基础。
This article will form the basis for our discussion.这篇文章将作为我们讨论的基点。
His experiments have laid a solid basis for further research.他们的实验为进一步的研究打下了坚实的基础。
What is the basis for your opinion?你的意见有什么根据吗？
I can't accept that as a basis for a decision.我不能同意把这一点作为决定的根据。
This theory seems to have no basis in fact.这一理论似乎没有实际的根据。
The basis of their friendship was common interest in sports.对体育运动的共同爱好是他们友谊的基础。
The basis of a good marriage is trust.美满婚姻的基础是信赖。
The basis of his business is making watches but he also sells jewelry. 他以生产手表为主，但也兼营珠宝。
The basis of this medicine is an oil. 这药的主要成分是一种油。
▲～+that-clause
Some videos have been banned on the basis that they are too violent.有些录像带因暴力镜头过多而被查禁。

basis, base, foundation
参见base条。

basis采用的是外来语的复数形式，即将-sis 变成-ses(读作［-siːz］)，而不是采用英语的规则复数形式-sises。这样，basis的复数形式就和base的复数形式相同了(但发音不同)。英语中好多以-sis结尾的名词都如此，注意不要混淆。

［同义词］   base, foundation, principle