Common Grammar Mistakes to Avoid in TOEFL Writing
Grammar errors can significantly impact your TOEFL Writing score, even if your ideas are strong and well-organized. The good news is that many test-takers make the same common mistakes, which means you can improve your score by focusing on these specific issues. This article identifies the most frequent grammar errors in TOEFL Writing responses and provides practical strategies to avoid them.
Why Grammar Matters in TOEFL Writing
Grammar accounts for a significant portion of your TOEFL Writing score. According to the official TOEFL scoring rubric, both writing tasks are evaluated on:
- Development and organization of ideas
- Use of supporting details and examples
- Language use, including grammar and vocabulary
- Writing conventions and overall accuracy
Even if your ideas are excellent, persistent grammar errors can limit your score to the mid-range (3 out of 5) or lower. Conversely, clean, error-free writing can help push your score into the highest range.
1. Subject-Verb Agreement Errors
Subject-verb agreement errors occur when the subject and verb don't match in number (singular or plural).
Common Mistakes:
Incorrect:
- The number of students in universities have increased.
- Each of the participants were given a survey.
- The professor, along with his assistants, are conducting research.
Correct:
- The number of students in universities has increased.
- Each of the participants was given a survey.
- The professor, along with his assistants, is conducting research.
How to Avoid This Mistake:
- Identify the main subject of the sentence (ignoring phrases between the subject and verb)
- Determine if the subject is singular or plural
- Make sure the verb matches the subject, not a noun that appears just before the verb
- Be careful with collective nouns (team, group, committee) which are usually singular in American English
2. Verb Tense Consistency
Shifting verb tenses inappropriately within a paragraph or even within a sentence is a common error that can confuse readers.
Common Mistakes:
Incorrect:
- The researcher conducted the experiment and then he publishes his findings.
- When students attended college, they are gaining valuable experience.
- Technology has improved our lives and changed how we communicate.
Correct:
- The researcher conducted the experiment and then he published his findings.
- When students attend college, they gain valuable experience.
- Technology has improved our lives and has changed how we communicate.
How to Avoid This Mistake:
- Decide on the main timeframe of your paragraph (past, present, or future)
- Use that tense as your primary tense throughout the paragraph
- Only shift tenses when there's a logical reason (e.g., describing something that happened at a different time)
- When editing, check each verb and ask if the tense is consistent with the surrounding context
Tense Selection Guide
- Present simple: For general truths, habits, and facts
- Present perfect: For actions that started in the past and continue to the present
- Past simple: For completed actions in the past
- Future: For predictions or plans
3. Article Usage (a, an, the)
Articles are particularly challenging for speakers of languages that don't have them (such as Russian, Japanese, and Korean).
Common Mistakes:
Incorrect:
- The education is important for success. (Incorrect use of "the" with abstract noun)
- I saw a interesting movie yesterday. (Should be "an" before vowel sound)
- Professor gave us homework. (Missing "The" before a specific noun)
Correct:
- Education is important for success.
- I saw an interesting movie yesterday.
- The professor gave us homework.
How to Avoid This Mistake:
- Use "the" for specific nouns that both the writer and reader know about
- Use "a/an" for non-specific singular countable nouns
- Use no article for abstract concepts and plural or uncountable nouns when speaking generally
- Use "an" before words that begin with a vowel sound (not just a vowel letter)
4. Preposition Errors
Prepositions (in, on, at, for, by, etc.) often follow different patterns in different languages, making them particularly challenging.
Common Mistakes:
Incorrect:
- Students often depend of their parents for financial support.
- The professor explained about the theory in detail.
- I arrived to the university at 9 AM.
Correct:
- Students often depend on their parents for financial support.
- The professor explained the theory in detail.
- I arrived at the university at 9 AM.
How to Avoid This Mistake:
- Learn common preposition collocations (words that typically go together)
- Create a personal list of preposition errors you frequently make
- Be aware that prepositions often can't be translated directly between languages
- When in doubt, check a collocation dictionary
5. Run-on Sentences and Comma Splices
Run-on sentences occur when two independent clauses are joined without proper punctuation or conjunctions. Comma splices happen when only a comma is used to join two independent clauses.
Common Mistakes:
Incorrect:
- The experiment was successful the researchers published their findings. (Run-on)
- The lecture was interesting, many students took detailed notes. (Comma splice)
Correct:
- The experiment was successful, and the researchers published their findings.
- The lecture was interesting; therefore, many students took detailed notes.
- The lecture was interesting. As a result, many students took detailed notes.
How to Avoid This Mistake:
- Identify independent clauses (complete thoughts that could stand alone as sentences)
- Join independent clauses with a coordinating conjunction (and, but, or, nor, for, so, yet) preceded by a comma
- Use a semicolon between closely related independent clauses
- Use a period to create separate sentences
- Use subordinating conjunctions (because, although, while, etc.) to show the relationship between ideas
6. Sentence Fragments
Sentence fragments are incomplete sentences that lack either a subject, a verb, or a complete thought.
Common Mistakes:
Incorrect:
- Because the student studied hard. (Subordinate clause without a main clause)
- The experiment conducted by the research team. (Missing verb)
- In the early morning hours. (Prepositional phrase without subject or verb)
Correct:
- Because the student studied hard, she passed the exam.
- The experiment was conducted by the research team.
- In the early morning hours, the students gathered to study.
How to Avoid This Mistake:
- Make sure every sentence has a subject and a verb
- Check that subordinate clauses (beginning with because, although, if, etc.) are connected to main clauses
- Ensure that each sentence expresses a complete thought
7. Pronoun Errors
Pronoun errors include problems with agreement, unclear references, and incorrect pronoun case.
Common Mistakes:
Incorrect:
- Each student must complete their assignment. (Singular/plural mismatch)
- The professor and me discussed the project. (Incorrect pronoun case)
- The book fell off the shelf and it broke. (Unclear reference - what broke?)
Correct:
- Each student must complete his or her assignment. (Or: All students must complete their assignments.)
- The professor and I discussed the project.
- The book fell off the shelf and the shelf broke. (Or: The book fell and broke.)
How to Avoid This Mistake:
- Ensure pronouns agree in number with their antecedents (the nouns they replace)
- Use subject pronouns (I, you, he, she, it, we, they) when the pronoun is the subject of a verb
- Use object pronouns (me, you, him, her, it, us, them) when the pronoun is the object of a verb or preposition
- Make sure it's clear what each pronoun refers to
8. Parallel Structure
Parallel structure means using the same pattern of words for two or more ideas that have the same level of importance.
Common Mistakes:
Incorrect:
- The professor enjoys teaching, research, and to write articles.
- The benefits of exercise include weight loss, improved mood, and you will have more energy.
- The student was asked to read the chapter, taking notes, and write a summary.
Correct:
- The professor enjoys teaching, research, and writing articles.
- The benefits of exercise include weight loss, improved mood, and increased energy.
- The student was asked to read the chapter, take notes, and write a summary.
How to Avoid This Mistake:
- When listing items, use the same grammatical form for each item
- Check lists that use "and" or "or" to make sure all elements match
- Pay special attention to items in a series, comparisons, and correlative conjunctions (not only/but also, either/or)
Editing Strategy
After writing your essay, read it backward, sentence by sentence. This disrupts the flow of ideas and helps you focus on the grammatical structure of each sentence in isolation.
Practical Strategies for Improving Grammar
- Create a personal error log: Keep track of the grammar mistakes you frequently make
- Practice targeted exercises: Focus on your specific problem areas
- Use grammar checkers: Tools like Grammarly can help identify errors (but don't rely on them completely)
- Read extensively: Exposure to correct grammar helps internalize patterns
- Edit in multiple passes: Focus on one type of error at a time
- Learn grammar rules: Understand the "why" behind corrections
- Get feedback: Have a teacher or proficient English speaker review your writing
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Final Thoughts
Improving your grammar for the TOEFL Writing section is a process that takes time and consistent practice. Focus on identifying and correcting the most common errors in your writing, and gradually you'll see improvement. Remember that even native English speakers make grammar mistakes, so don't be discouraged. The goal is not perfection but rather clear, effective communication with minimal errors.
As you practice, pay attention to the feedback you receive and actively work on your problem areas. With dedication and the right strategies, you can significantly reduce grammar errors in your TOEFL Writing responses and improve your overall score.
