1. Use commas set off introductory elements of the sentence. Sometimes, at the beginning of a sentence, the conjunctive adverbs (or adverbial conjunction) will act as a kind of summing up device or transition, and when it does, it is often set off from the rest of the sentence with a comma:
有時，在句首，副詞連接詞作為總結語或轉折語時，用逗點隔開其餘的句子 (please see http://grammar.ccc.commnet.edu/grammar/transitions.htm#transitions for the list of 副詞連接詞 that apply)
(a) Accidentally, he stepped on a dog’s shits.
=> Accidentally 副詞用來形容主要子句 “he stepped on a dog’s shits”.
= He stepped on a dog’s shits accidentally.
(b) Gradually, he has come to his senses.
= He has come to his senses gradually.
(a) So, the sheriff peremptorily removed the child from the custody of his parents
=> So 副詞連接詞作為總結語
(b) Still, I am uncomfortable staying with him.
=> Still 副詞連接詞作為轉折語
2. Use commas to set off non-essential elements of the sentence.
(a) Vegetable, which is good for your health, should be eaten everyday.
= Vegetable should be eaten everyday.
=> Vegetable (名詞) 主詞.
Which is good for your health 句子中的非必要的資料(用來形容主詞 Vegetable) , 可省略.
3. Use a comma to set off parenthetical elements such as appositives. When both a city's name and that city's state or country's name are mentioned together, the state or country's name is treated as a parenthetical element.
用逗點隔開插入語, 例如同位語, 或城市，國家等
(a) Tom, a college professor, recently made up his mind to run for the next Mayor's election.
=> Tom (名詞) 與 a college professor 是同位語
(b) Taipei , Taiwan , boasts having the best seafood in the world.
4. Use a comma to avoid confusion.
Outside, the garden was cluttered with a huge variety of flowers.
=> Without the comma, it will mean “outside the garden” instead of “outside”, and the grammar will be inaccurate.
(不用逗號正確語法: Outside the garden were clusters of a huge variety of flowers.)
** 版權所有 - Elisa