一、比较对象不一致
在英语的比较句型中，两个待比较的对象应具有可比性，这也就是语法上说的比较对象的一致性问题。有的同学在进行英语写作时，经常忽略这个一致性问题，从而写出一些不合英语习惯的句子。如：
误：The population of China is much larger than Japan.
正：The population of China is much larger than that of Japan.
析：the population of China 应与 the population of China比较，而不能与 Japan 比较，即误句主要错在比较对象不一致。注意，为避免重复，正句中的the population of China用that of China代替。
误：The style of the new building is different from the old one.
正：The style of the new building is different from that of the old one.
正：The new building is different from the old one in style.
析：用different表示比较时，也要注意比较对象的一致性。就本题而言，新的 style 应与旧的 style 比，或新的building与旧的 building 比，而不能将两者混在一起。
二、主谓不一致
在英语中，句子的主语和谓语动词在人称和数上必须一致。由于受汉语的影响，许多同学在写作时经常忽略句子的主谓一致关系，从而造成错误。如：
误：Anyone can borrow the books, and it cost nothing to borrow them.
正：Anyone can borrow the books and it costs nothing to borrow them.
析：第一个分句的时态是一般现在时，故第二个分句中的动词cost不可能是动词的过去式，且由于句子主语是it，故谓语动词应用一般现在时costs，而不能用过去式cost。
误：He as well as his parents have been to the Great Wall.
正：He as well as his parents has been to the Great Wall.
析：当作主语的名词或代词后有as well as, in addition to, including, with, along with, together with, but, except等引导的成分时，谓语动词的单复数仍由其前的主语决定。再如：My English teacher together with his family is from England.
误：Not only John but also I are going to Shanghai next week.
正：Not only John but also I am going to Shanghai next week.
析：在由not only…but also…, not just…but…, or, either…or…, neither…nor…连接主语的句子中及在there be句型中，谓语动词的单复数按就近原则处理，即按与谓语动词最靠近的那个主语来确定谓语动词的单复数形式。如：Neither you nor she is a teacher.
三、单复数不一致
名词有可数和不可数之分，而可数名词又有单数与复数之区。在英语写作中，名词单复数问题也是许多同学经常忽略的一个问题。如：
误：On the way home I took a lot of picture because since the scenery was so beautiful. I’ll have them developed this afternoon.
正：On the way home I took a lot of pictures because the scenery was so beautiful. I’ll have them developed this afternoon.
析： take picture中的picture为可数名词，根据下文中的them可知，此处应用复数形式pictures。
误：He has been working so hard recently that he has got good mark in all his subjects.
正：He has been working so hard recently that he has got good marks in all his subjects.
析：从后面的subjects来看，mark应用复数形式，说的是在各科考试中都取得了好分数。
四、非谓语形式不一致
动词的非谓语形式一直是英语学习中的一个难点，而动词非谓语形式的一致性问题更是许多同学经常忽略的一个问题。如：
误：To know what is good and doing what is right are two different things.
正：To know what is good and to do what is right are two different things.
析：由and 连接的两部分为并列主语，前一部分用不定式结构，后一部分也应用相同的结构。
误：Fishing is his favourite hobby, and to collect coins is also his hobby.
正：Fishing is his favourite hobby, and collecting coins is also his hobby.
析：误句的问题就在于句子不平行(不一致)，因为and前后都为句子，按英语习惯其结构形式应该一致。
五、代词不一致
代词一致的问题主要存在于性别一致、数的一致(单复数问题)和代词的格等方面。如：
误：There are forty students in our class, and thirty of them are boys.
正：There are forty students in our class, and thirty of us are boys.
析：从前一分句可看出，本句谈论的是“我们班”的情况，故后一分句也应用第一人称。
误：Once one has money, we can do what he wants (to do)
正：Once one has money, he can do what he wants (to do)
析：误句中前面提到的是one has money，面又有what he wants，we与前后代词不一致，故应改为he。
六、搭配不一致
搭配不一致主要指句中的固定搭配应保持完整并与上下文一致。如：
误：He worked so hard as he could catch up with his classmates.
正：He worked so hard that he could catch up with his classmates.
析：从固定形式上看，有so…as…,so …that… 等。但从句意上看，此处应该用so…that…，才能保持句意及结构的一致。
误：I was so tired that I fell asleep at the moment my head touched the pillow.
正：I was so tired that I fell asleep the moment my head touched the pillow.
析：此处the moment是名词用作连词，表示“一……就……”，其前不能加at。
七、逻辑主语不一致
按英语习惯，当非谓语动词作状语时，其逻辑主语应与句子主语保持一致，否则便会造成错误。如：
误：After reading the letter, tears ran down his cheeks.
正：After he read the letter, tears ran down his cheeks.
正：After reading the letter, he burst into tears.
析：after 引导动名词作状语时，要注意其逻辑主语与句子主语保 持一致。
误：Given more time, the work could have been done better.
正：Given more time, we could have done the work better.
析：在上句中，given 是 give(给)的过去分词，given more time为过去分词短语，在句中用作状语，表示条件，相当于 If we had been given more time。按照英语语法，分词短语用作状语，它的逻辑主语必须与句子主语保持一致。