考研英语二写作标点符号的运用之逗号
如今越来越多的人为了快捷省事，喜欢用空格代替标点符号，社交可以不带标点交流，但是考试不带标点写作可就事大了，甚至标点用错都会被扣分。如果因为标点符号扣分，那就冤枉了！
考研英语二写作，你的关注点是否都在词句、语法、逻辑上，标点符号却被遗忘在了角落？
但是标点符号用不好，文章脉络一团糟，句子内外部没有连贯性，很可能导致扣分。相反，如果标点符号运用得当，会让文章更具感情色彩和可读性，能给文章添色加彩提分数。
所以，千万别小看了标点符号的作用，或许你差的那1分，就是标点用错了~下面，就看看各个标点符号都该怎么用，别再一“.”到底啦！
1.在并列连词(and,but,for,nor,or,yet)前使用，用来连接句中的各分句。
The principal reason for this is that noneof them possesses chlorophyll,and since they cannot synthesize their owncarbohydrates,they obtain their supplies either from the breakdown of deadorganic matter or from other living organisms.
2.用逗号来分隔一系列单词、词组和从句。
Furthermore the walls of fungal cells arenot made of cellulose,as those of plants are,but of another complex sugarlike polymer called chitin,the material from which the hard outer skeletons ofshrimps,spiders,and insects are made.
They are a major cause of structural damageto building timbers,a cause of disease in animals and humans,and one of thegreatest causes of agricultural losses.
3.逗号用来分隔与句子其他部分密切相连的简短插入语或旁白。(较长的，更为突兀的或复杂的插入成分的则用破折号或圆括号。)
Chemical fertilization,for example,helpsto produce better crops,but is harmful to the environment.
4.在并列形容词，即分别修饰同一个名词的形容词之间使用逗号，但也有的形容词之间不加逗号的。
For men,heroism was usually described asbravery and the active,successful over coming of adversity.

5.用逗号来分隔非限定性修饰语，即该修饰语对于句子的意义并非必不可少。非限定性修饰语与限定性修饰语的区别在于，它即使被省略，也不会改变句子的主要意思。
(1)同位语。
The canopy,the upper level of the trees inthe rain forest,holds a plethora of climbing mammals of moderately large size,which may include monkeys,cats,civets,and porcupines.
(2)从句。
The canopy,the upper level of the trees inthe rain forest,holds a plethora of climbing mammals of moderately large size,which may include monkeys,cats,civets,and porcupines.
6.逗点用于直接引用的句子之前，如Mary said,"Let's go fishing."（如果是引用比较正式的发言讲话就要用冒号，一般情况下就用逗点。）在反问句之前要使用逗点:He worked very hard,didn't he?