1、表示文中的人说的话。
i've been thinking about this afternoon, you know,said halliday rather suddenly.
2、引用单词或短语。
how do you spell the word “across”?
3、不寻常的词语也常用引号，以引人注意。
the noun to which a relative pronoun refers is called the “antecedent” of the pronoun.
关系代词所指代的名词唤作关系代词的“先行词”。
4、书名和诗文名也用引号。
have you read, “the jungle”?
你读过《屠场》吗？