1、主谓不一致
例. When one have money ,he can do what he want to. (人一旦有了钱，他就能想干什么就干什么。)
剖析：one是单数第三人称，因而本句的have应改为has;同理，want应改为wants。本句是典型的主谓不一致。
改为：Once one has money, he can do what he wants (to do).
2、词性不一致
“词性不一致”常表现为：介词当动词用;形容词当副词用;名词当动词用等。
例. None can negative the importance of money.
剖析：negative 系形容词，误作动词。
改为：None can deny the importance of money.
3，句子前后不一致
托福写作中的句子前后不一致是指一个句子前言不对后语，或是结构上不畅通，这也是考生常犯的毛病。
例. The fresh water, it is the most important things of the earth.
剖析：The fresh water 与逗号后的it 不连贯。It 与things 在数方面不一致。
改为：Fresh water is the most important thing in the world.
4，指代对象不一致
这里的指代对象不一致主要讲的是代词与被指代的人或物关系不清，或者先后所用的代词不一致。把这一项单独提出来是因为大家实在很青睐这一部分：
Mary was friendly to my sister because she wanted her to be her bridesmaid. (玛丽和我姐姐很要好，因为她要她做她的伴娘。)
读完上面这一句话，读者无法明确地判断两位姑娘中谁将结婚，谁将当伴娘。如果我们把易于引起误解的代词的所指对象加以明确，意思就一目了然了。这个句子可改为：
Mary was friendly to my sister because she wanted my sister to be her bridesmaid.
例. And we can also know the society by serving it yourself.
剖析：句中人称代词we 和反身代词yourself指代不一致。
改为：We can also know society by serving it ourselves.
