这几个不能出错。托福写作考试最考验大家的就是语法问题，语法使用的好不好完全反应在大家平时的练习中，如果同学们真的用尽全力复习了，我不相信你的语法还能出现下面的这些错误。
1、托福写作比较对象的对等
在比较结构中，注意前后比较事物要对等。常用that和those来指代“比较结构”里先前提到的名词。
比如：The merits of serious movies far outweigh funny movies.
应改为：The merits of serious movies far outweigh those of funny movies.(those指代的是前半句的比较对象merits)
2、托福写作句子不完整
不完整句子指的是句子当中缺少主语或谓语等，无法形成一个完整的句子。
比如：A movie that inspires deep emotions.(只有名词加定语从句，不是完整的句子)
应改为：She went to see “The Silver Star”, a movie that inspires deep emotions.
3、托福写作句子不间断
不间断句子指的是用逗号来连接两个完整的句子。
比如：There is increasingly widespread reliance on electronic mail, some people still resist using it, especially those who prefer handwritten letters.
应改为：Although there is increasingly widespread reliance on electronic mail, some people still resist using it, especially those who prefer handwritten letters.(根据两句之间的关系，加入连词)
4、托福写作句子主谓不一致
主谓不一致指的是句子中主语与谓语没有保持数的一致。
比如：Many students thinks tomorrow is a holiday.
应改为：Many students think tomorrow is a holiday.
再比如：The use of cell phones during concerts are not allowed.
应改为：The use of cell phones during concerts is not allowed.
5、托福写作可数名词完整
可数名词“裸奔”指的是可数名词之前没有冠词，也没有变为复数形式。
比如：Even expert or scholar specializing in a certain field might cover a vast spectrum of knowledge in order to succeed.
应改为：Even experts or scholars specializing in a certain field might cover a vast spectrum of knowledge in order to succeed.(可数名词变复数形式)
6、托福写作but和however用法
but和however都表示转折，但是but是连词，而however是副词，也就是说however是不能来连接两个独立分句的。
比如：Printed books are limited in space, however, space is not an issue for electronic ones.
应改为：Printed books are limited in space. However, space is not an issue for electronic ones. (用句号将原句分成两个独立分句)
这几个托福写作问题不能出错。如果大家在语法上还有不明白的地方，请抓紧时间咨询网的老师获得帮助吧。