上一期新航道雅思小编分享的有关分号的用法中提到了雅思考试对于标点的要求：分号用法知多少？，标点误用会直接引起读者阅读障碍和对信息的歧义理解。可是，我们最常用的标点之一——逗号，我们在语言输出过程中都用对了吗？

　　逗号用法1：分隔并列项

　　A, B, and C

　　解析：连接大于等于三者以上的并列项,注意连词前有逗号。

　　‘The glass industry is aware of the issue,’ says Brian Waldron, chairman of the standards committee at the Glass and Glazing Federation [,] a British trade association [,] and standards development officer at Pikington. (例子出处:剑15 T4R)

　　A, B and C

　　解析：有时候避免太过于考究，可以省略连词前的逗号。

　　A country’s history [,] language and ethos are all inextricably bound up in its manufactured artifacts. (例子出处:剑10 T3WT2)

　　逗号用法2：分隔非句子成分

　　四种写法

　　副词/介词词组/非谓语结构,独立句子

　　解析：逗号连接句首的副词/介词词组/非谓语结构和后面的独立句子。

　　Since then [,] so many other examples have been discovered that it no longer makes sense to say that evolution is as good as irreversible. (例子出处:剑10T4R)

　　主语, 副词/介词词组/非谓语结构,谓语及句子其他成分

　　解析：双逗号隔开句中的副词/介词词组/非谓语这三类结构。

　　The International Institute of Noise Control Engineering [,] on the advice of the World Health Organization [,] has established an international working party.’(例子出处:剑9T2R)

　　独立句子, 副词/介词词组/非谓语结构

　　解析：逗号连接部分句末出现的副词/介词词组/非谓语结构。

　　The gender difference is smallest at the level of Bachelor’s degree [,] however. (例子出处:剑4T3WT1)

　　名词,同位语,句子其他成分或者名词,同位语。

　　解析：句子中名词后面的同位语，用双逗号隔开其与句子主干；如果是句末名词的同位语，句末自然句号落尾。

　　Clemmons contacted Morteza Gharib [,] aeronautics professor at the California Institute of Technology. (例子出处:剑7T4R)

　　逗号用法3：与连接词一起连接句子

　　两种写法

　　连接词独立句子,独立句子

　　解析：逗号与连接词一起连接两个独立句子，这类常用连接词通常是状从从属连词如Because/If/Although/When/where等。

　　例句：If this is not true [,] then we would be able to predict he behavior and character of a person from the moment they were born. (例子出处:剑5T4WT2)

　　独立句子,连接词独立句子

　　解析：状从从属连词可放两句中间；另外置于中间的连接词还包括平行关系的连词如and/while/but/or以及非限定性定从从属连词which /who/whose/whom等。

　　Interest in sport is not universal [,] and additional facilities might simply attract the already fit. (例子出处:剑9T3WT2)

　　This has the added benefit that parents and children often use them together just for fun [,] which develops a positive attitude to exercise at an early age. (例子出处:剑9T3WT2)

　　小 结

　　这三种用法中，第三种是我们在写作中最容易用错并引起歧义的地方了。切记逗号不能一“逗”到底任意连接两个没有连接词的句子也不可以让连接词连接一个独立句子。