將打算隔出來 (parenthetic) 的句子用逗點包起來 (II)

我們不可以在限定的名詞內插入逗點。

• Billy the Kid
• The novelist Jane Austen
• William the Conqueror
• The poet Sappho
  

Junior 這個字 (通常會縮寫成 Jr.)，一般認為是需要用逗點隔開的，但是，邏輯上來說，
這個字應該是限定的，所以不需要加逗點。

• James Wright Jr.
  

非限定關係子句需要被隔開，就像是由連接詞引出、用來補充說明時間或地點的子句一樣。
因此需要加上逗點。非限定子句的目的並不是要辨識或定義其前方的名詞；只是要補充說明而已。

• The audience, which had at first been indifferent, became more and more interested.
• In 1769, when Napoleon was born, Corsica had but recently been acquired by France.
• Nether Stowey, where Coleridge wrote The Rime of the Ancient.
• Mariner, is a few miles from Bridgewater.
  

上述句子中，which、when、以及 where 所引出的子句都是非限定的；其用途並非「限制」與「定義」，
他們只是用來補充說明一些事情而已。以第一個例子來說，which 所引出的子句，並非要指出是哪位聽眾；
這個我們應該都已經知道了。這個子句，對主要子句提供額外的補充說明。以上每個例子，
都是由兩個可以獨立存在的句子所組合而成的。

• The audience was at first indifferent. Later it became more and more interested.
• Napoleon was born in 1769. At that time Corsica had but recently been acquired by France.
• Coleridge wrote The Rime of the Ancient Mariner at Nether Stowey.
  Nether Stowey is a few miles from Bridgewater.
  

限定子句就不一樣了；其不需分隔，也不能加逗點。因此，

• People who live in glass houses shouldn’t throw stones.

這裡 who 所引出的子句是用來指出究竟是哪些人；這個句子與之前的不同，是無法被切成兩個獨立的句子的。
以上的逗點使用原則，一樣可以套用在分詞片語與同位語。

• People sitting in the rear couldn’t hear. (限定的)
• Uncle Bert, being slightly deaf, moved forward. (非限定)
• My cousin Bob is a talented harpist. (限定)
• Our oldest daughter, Mary, sings. (非限定)
  

當主要子句前方有一個片語或是從屬子句時，利用逗點將他們隔開。

• Partly by hard fighting, partly by diplomatic skill, they enlarged their dominions to the east and
  rose to royal rank with the possession of Sicily.