TOEFL Grammar: The 10 Rules That Cost Points in the 2026 Test

Aswathy Mohandas

03/11/2026

12 min read

TOEFL grammar is not a separate section, but it is scored almost everywhere. In the 2026 TOEFL iBT, ten Build a Sentence items test sentence structure directly, and the Email, Academic Discussion and Interview tasks are scored partly on how accurately you use grammar. A small set of rules causes most of the lost points: question word order, verb tenses, articles, agreement and sentence boundaries.

This guide covers the ten grammar areas that cost the most, task by task, each with an original wrong and right example, plus a short exercise at the end. The task details come from ETS’s TOEFL iBT test content page, its Writing section and Speaking section pages, and the TOEFL iBT 2026 Update test specifications, checked 31 October 2026. Every example sentence on this page is original.

Where does grammar count on the 2026 TOEFL?

The TOEFL iBT changed in January 2026. The Writing section now has three task types (Build a Sentence, Write an Email and Write for an Academic Discussion) in 12 items and about 23 minutes. The Speaking section has two (Listen and Repeat and Take an Interview) in 11 items and about 8 minutes. Grammar plays a part in all five.

Source: ETS test content page, Writing and Speaking section pages and the 2026 test specifications (pages 2, 6, 7 and 15), checked 31 October 2026. ETS notes that the specifications may have minor revisions, and that test time and items may vary.

Two things stand out. First, the specifications give Build a Sentence 10 of the Writing section’s 20 raw points, so half the section’s raw points come from sentence structure alone. Second, ETS says the AI scoring of written and spoken answers looks at features “like fluency, coherence, and grammar”, while its Writing page adds that scoring focuses on communicating clearly, “not on writing a perfect first draft”. A slip here and there will not sink an answer. Repeated errors in the same basic structure will hold it down. Each section is then reported on the 1 to 6 scale; our guide to TOEFL scores explains how the sections combine.

Which grammar rules cost points in Build a Sentence?

Each Build a Sentence item is worth at most 1 point and is machine scored, and ETS does not describe any partial credit, so one misplaced word can cost the whole item. Most items turn on where the verb and the subject go, especially in questions.

1. Word order in direct questions

In a direct question, an auxiliary verb (do, does, did, will, can, have, is) comes before the subject. If the question has no other auxiliary, English adds do, does or did, and the main verb goes back to its base form.

• Wrong: Where the shuttle stops on weekends?
• Right: Where does the shuttle stop on weekends?

If the word chunks include does or did, the main verb must be in its base form (stop, not stops or stopped). If they include will or can, it goes straight after the question word: When will the grades be posted?

2. Embedded (indirect) questions

When a question sits inside another sentence, after phrases like Could you tell me, Do you know or I wonder, it goes back to statement order: subject, then verb. No inversion, and no added do.

• Wrong: Could you tell me when is the next advising session?
• Right: Could you tell me when the next advising session is?

This is the classic Build a Sentence trap, because the chunk with the question word makes the sentence look like a direct question. The same rule matters in emails, where polite requests are often embedded questions: Do you know what time the lab opens?, not what time does the lab open?

For a practice set of five Build a Sentence items with answers, see our TOEFL writing practice test.

Which grammar mistakes cost points in Write an Email?

The Email task asks you to make a request, give information or propose a solution in an academic or social situation. ETS says it measures whether you write clearly, stay on topic and follow basic writing conventions. Four kinds of error turn up again and again in student emails.

3. Past simple versus present perfect

Use the past simple with a finished time (yesterday, last week, on Monday). Use the present perfect for something that started in the past and continues, or for a past event with no time stated.

• Wrong: I have submitted the form last Tuesday, but I have not received a reply.
• Right: I submitted the form last Tuesday, but I have not received a reply.

The second half of the right version stays in the present perfect because the wait is still going on. The same logic applies to since and for: I have been a member of the debate club since 2024, not I am a member since 2024.

4. Articles: a, an and the

Use a or an the first time you mention one countable thing, and the when the reader knows which one you mean, often because you have already mentioned it. A singular countable noun almost never stands alone.

• Wrong: I attended workshop on citation styles, and workshop helped me fix my references.
• Right: I attended a workshop on citation styles, and the workshop helped me fix my references.

Choose between a and an by sound, not spelling: an hour, an MBA, but a university and a one-day extension.

5. Uncountable nouns

Some common academic nouns are uncountable in English. They take no plural -s and no a/an: information, advice, feedback, research, equipment, homework, evidence and furniture.

• Wrong: Could you send me more informations about the internship and some advices on applying?
• Right: Could you send me more information about the internship and some advice on applying?

To count them, add a countable word: a piece of advice, two pieces of evidence.

6. Gerund or infinitive after a verb or preposition

After a preposition (in, about, for, and the to in look forward to), the verb takes the -ing form. Some verbs, such as suggest, avoid, consider and mind, are also followed by -ing, while others, such as want, plan and hope, take to plus the base form.

• Wrong: I am interested in join the research group, and I look forward to meet you on Friday.
• Right: I am interested in joining the research group, and I look forward to meeting you on Friday.

Because I look forward to hearing from you is such a common email closing, getting it wrong is easy to spot. Requests follow the same rule: Would you mind extending the deadline?, not Would you mind to extend.

Which grammar mistakes cost points in the Academic Discussion task?

In Write for an Academic Discussion you join an online class discussion, state your opinion and support it. The ETS specifications describe it as academic paragraph text that presents a clear, well-supported argument using varied grammar and vocabulary. Longer, more complex sentences show range, but they are also where these four errors appear.

7. Subject–verb agreement with long subjects

The verb agrees with the head of the subject, not with the noun closest to it. Phrases such as the number of, one of and each of take a singular verb, even when a plural noun comes before the verb.

• Wrong: The number of students who take evening classes have increased in recent years.
• Right: The number of students who take evening classes has increased in recent years.

Compare A number of students have, which is plural because it means “many students”. Similarly, One of the main reasons is, never are.

8. Sentence boundaries: comma splices and run-ons

A comma cannot join two complete sentences on its own. Use a full stop, a semicolon, or a linking word such as because, so or although. Words like however and therefore do not join sentences either.

• Wrong: I agree with Priya, group projects teach students to share responsibility, however they can be unfair to the hardest worker.
• Right: I agree with Priya because group projects teach students to share responsibility. However, they can be unfair to the hardest worker.

The opposite error is a fragment, a clause left on its own: Because many students work part-time. Attach it to the sentence it explains.

9. Conditionals

In a real (first) conditional, the if clause takes the present simple, not will. In an imagined (second) conditional, the if clause takes the past simple, and formal writing uses were for every subject.

• Wrong: If the university will extend library hours, more students will study on campus.
• Right: If the university extends library hours, more students will study on campus.

Academic Discussion prompts often ask what you would do in someone else’s position, which calls for the second conditional: If I were the dean, I would make the first year pass/fail, not If I would be the dean.

10. Comparatives and superlatives

Short adjectives add -er or -est (cheaper, the cheapest); longer ones use more or the most (more flexible, the most effective). Never use both, and remember the irregular forms better and worse.

• Wrong: Studying in a group is more better than studying alone, and it is also more easier to stay motivated.
• Right: Studying in a group is better than studying alone, and it is also easier to stay motivated.

Since most discussion answers compare two options, check every comparison: than (comparing) is not then (time).

How does grammar affect TOEFL Speaking?

In Listen and Repeat you repeat short sentences exactly as you hear them. The small grammatical pieces are the easiest to drop: past-tense -ed endings, plural and third-person -s, and articles. The ETS specifications describe lower-level responses as ones that “omit or substitute words”, while the highest level repeats complex sentences “with high accuracy”. Knowing the grammar helps you hear and keep those endings, because you expect them.

In Take an Interview you answer questions about your experiences and opinions, and ETS lists accurate grammar alongside varied vocabulary and intelligible speech. Tense control matters most, because interview questions jump between past experiences and present opinions.

• Wrong: Last year I join a volunteer group, and since then I learn a lot about teamwork.
• Right: Last year I joined a volunteer group, and since then I have learned a lot about teamwork.

For interview-style practice questions, see our TOEFL speaking questions guide.

What are the ten rules at a glance?

Can you spot the error? A five-sentence check

Each sentence below has one grammar error. Fix it before you read the answers.

1. Can you tell me where is the registrar’s office?
2. Each of the proposals have clear strengths.
3. I have met Professor Lin at the orientation last semester.
4. The lab needs more equipments before the new term.
5. If students will get feedback earlier, they will improve faster.

Answers:

1. Can you tell me where the registrar’s office is? An embedded question takes statement order (rule 2).
2. Each of the proposals has clear strengths. The head of the subject is each, which is singular (rule 7).
3. I met Professor Lin at the orientation last semester. Last semester is a finished time, so use the past simple (rule 3).
4. The lab needs more equipment before the new term. Equipment is uncountable (rule 5).
5. If students get feedback earlier, they will improve faster. No will in the if clause of a real conditional (rule 9).

How should you practise TOEFL grammar?

• Keep an error log. After each practice email or discussion answer, note which of the ten rules you broke. Most test takers repeat the same two or three, and those are the ones to drill.
• Proofread for one rule at a time. In the last minute of a writing task, scan once for verbs (tense and agreement) and once for nouns (articles and plurals). One focused pass catches more than a general re-read.
• Start Build a Sentence with the verb. Find the main verb and any auxiliary first; they decide where the subject and the question word go.
• Write in the real format. Grammar drills help, but the errors that cost points show up under time pressure. Practise full emails and discussion posts on a timer, and see how high-scoring answers handle these structures in our TOEFL writing samples for the 2026 format.
• Pair grammar with word choice. Accurate grammar and precise vocabulary are scored together; our TOEFL iBT vocabulary guide covers the word side.

The fastest way to find out which rules are costing you points is to sit the test format under time. Take our free TOEFL practice test with all four sections in the 2026 format, then check your Writing and Speaking answers against the ten rules above.

Planning where to apply with your TOEFL score? Our admissions counsellors can help you shortlist universities that match it.