As you know, in English you generally make a word plural by adding an ‘s’ at the end. There seems to be some confusion, though, about how to make plurals of terms made up of more than one word. For example, do you say bicycles shops or bicycle shops? Do you say power of attorneys or powers of attorney?
众所周知，在英语中要把一个名词变成复数，只要在这个词的后面加上“s”就行了。不过，当一个名词变成了由几个名词组成的`词组时，就让人摸不着头脑了。举个例子，如果你要表示自行车商店的复数形式，你是用“bicycles shop”还是“bicycle shops”?在表示授权书的复数时，你是说“power of attorneys”还是“powers of attorney”?
The answers are bicycle shops and powers of attorney.
正确的说法是“bicycle shops”和“powers of attorney”。
The rule is that you pluralise the “head” of the term.
The term bicycle shop is typical of most noun groups. The “head” is the last word in the group. The previous word or words act as an adjective. So the last word in the group is pluralised. Here are some more examples:
Bank account => Bank accounts
Service charge payment => Service charge payments
Employee share option scheme => Employee share option schemes
Company car => Company cars
Price limit => Price limits
Termination notice => Termination notices
However, a term like power of attorney acts rather differently. Power is the “head” and of attorney is an adjectival phrase which describes the “head”. Here are some other examples of terms that behave in the same way:
Article of association => Articles of association
Code of conduct => Codes of conduct
Conflict of interest => Conflicts of interest
Course of action => Courses of action
Notary public => Notaries public
Statement of claim => Statements of claim