六、标点符号用法讲练
标点符号 (Punctuation Marks) 主要用来明确语句的含义，标示一个句子或句子中各个成分的起止，以及彼此间的语法或语义上的关系。常用的标点符号有：
i) 句号 ( . ) (Period, Full Stop)
ii) 问号 ( ? ) (Interrogation Mark)
iii) 感叹号 ( ! ) (Exclamation Mark)
iv) 逗号( , ) (Comma)
v) 分号( ; ) (Semicolon)
vi) 冒号( : ) (Colon)
vii) 破折号 ( — ) (Dash)
viii) 括号( [ ] ) (Parentheses)
ix) 引号 ( “ ” )(Quotation Marks)
x) 连字号 ( - ) (Hyphen)
xi) 撇号( ’ ) (Apostrophe)
xii) 删节号 (…) (Ellipsis)
上列标点符号，可归纳为三种情况：i) — iii) 用于句尾；iv) — ix) 用于句中；x) —xi)用于词内。最后一个符号常用于引文中，表示删掉一些文字。

（一）主要标点符号的用法
1) 逗号 (Comma)
主要用于：
a) 并列的词或句子。例如：
Solids , liquids and gases can be changed from one to another.
From l926 until his death in l953, Thorpe lived a poor , lonely , unhappy life.
There’s only enough room for people to walk in , take one of the eleven inserts , roll them together , slip a rubber band around them and slide them into a plastic bag.
The present is living , the past dead , and the future unknowable.
b) 状语(包括从句，动词-ing形式，独立结构，不定式短语，介词短语等)。例如：
When water is heated , it will be changed into vapour.
John , seeing that his brother was hurt , ran to help him. 或Seeing that his brother was hurt , John ran to help him.
Work is done , even by a force acting at a distance.
To make the trip more exciting for the kids , Oscar kept the destination a secret.
After the heartbreaking experience , Thorpe turned to professional sports.
c) 非限定形容词从句或插入语。例如：
At l0 a.m.we arrived at the railway station , where Jane was waiting for us.
You know , of course , what a phrasal verb is. I needn’t , therefore , explain it now.
d) 呼语、同位语。例如：
George , tell Dick the answer to the question.
He was a direct descendant of the famous warrior chief , Black Hawk.
e) 日期、数字、地址。例如：