同学你好，该知识点来自沪江网校《Hitalk商务口语初级至中级（A）【现金奖励班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学好，
最可靠的办法是查字典，助教也是按照字典为同学解答的，
service, satisfation, supply, care, expectation, requirement 这些都是表示概念的抽象名词，一般为不可数，但是前面有具体形容词修饰时，形容词前可以加a；有的词直接加s表示复数。

service
https://en.oxforddictionaries.com/definition/service
1.1count noun An act of assistance.
‘he has done us a great service’

expectation
https://en.oxforddictionaries.com/thesaurus/expectation
3‘a young man of expensive habits and no expectations’

supply
https://en.oxforddictionaries.com/definition/supply
‘he meant to go, but time and petrol were in short supply’这种固定搭配in short supply就没有a, 所以有规则就有例外。（没有永远不变的规则。）

care
https://en.oxforddictionaries.com/definition/care
加a和不加a的情况都有。
‘he planned his departure with great care’
‘she was driving along without a care in the world’

requirement
https://en.oxforddictionaries.com/definition/requirement
‘applicants must satisfy the normal entry requirements’

同学在字典上或权威英语网站上看到了，就可以放心用，没见到，就先别用，此规则同样适用于其他中国特色名词翻译。

祝进步。