原文

1. Form the possessive singular of nouns with 's.
單數(shù)名詞的所有格在后面加’s

Follow this rule whatever the final consonant. Thus write,
無論單詞以什么輔音字母結(jié)尾，都要遵守這條規(guī)則，寫成：

Charles's friend
Burns's poems
the witch's malice

This is the usage of the United States Government Printing Office and of the Oxford University Press.
美國政府印刷局和牛津大學(xué)出版社都遵循這一規(guī)則。

Exceptions are the possessives of ancient proper names in -es and -is, the possessive Jesus', and such forms as for conscience' sake, for righteousness' sake. But such forms as Achilles' heel, Moses' laws, Isis' temple are commonly replaced by
例外包括以es或is結(jié)尾的古代專有名詞，耶穌的所有格Jesus’，以及for conscience’ sake，for righteousness’ sake這類型短語。然而，Achilles' heel，Moses' laws，Isis' temple等短語通常寫成以下形式：

the heel of Achilles
the laws of Moses
the temple of Isis

The pronominal possessives hers, its, theirs, yours, and oneself have no apostrophe.
所有格代詞（hers，its，theirs，yours，oneself）不加撇號。

注解

單數(shù)名詞的所有格并沒有嚴格的標準，bus'和bus's都可以。大家可以按照《風(fēng)格的要素》里的建議，全部加's。

以s結(jié)尾的復(fù)數(shù)名詞的所有格直接加’。具體規(guī)則可以參考《坑爹的'和's 撇號的兩大用法誤區(qū)（下）》。