120 short grammar rules in 12 topics, each with one correct sentence, a common mistake to avoid, and the TOEFL tasks where it matters.
Test Ninjas Research · Updated October 1, 2026
The 2026 TOEFL has no grammar section, but grammar is everywhere in it. In Build a Sentence, word order and verb forms decide whether an answer is right at all. In Complete the Words, endings such as -s and -ed are part of what you restore. In emails, discussion posts and interview answers, grammar decides how easily someone can follow you. These rules focus on those uses rather than on terminology.
Each card is original Test Ninjas teaching material with links to the reference page it was checked against. ETS does not publish a grammar syllabus, so treat the topic list as a study plan, not a list of what the test covers.
The 12 topics by level
Level
Topics
Easy
Sentence foundations; Nouns and determiners; Basic verb forms; Questions and everyday word order
Medium
Time and aspect; Clauses and connections; Verb complements and voice; Reference and comparison
Hard
Advanced clause structure; Conditionals and modality; Academic cohesion and punctuation; Agreement and parallelism
Every sentence needs a few things in place: a subject, a finite verb, and words in an order English readers expect. These rules sound basic, but missing subjects, fragments and comma-joined sentences are exactly the errors that make a Build a Sentence arrangement wrong or an email sentence read as broken.
10 rules: Complete statements · Statement order · Imperative verbs · Linking be · Joining two statements · Weather subject it · Subject pronouns · Object pronouns · Dependent-clause fragments · Adverb before a main verb
Small words in front of nouns — a, an, the, this, many — and the endings on the nouns themselves carry a lot of information. They decide whether you mean one thing or several, a specific thing or any thing. In Complete the Words, a missing plural ending or article is often exactly what you have to restore.
10 rules: Singular count nouns · Regular plurals · Irregular plurals · Noncount nouns · A or an by sound · No a before a plural · The for an identified item · Many with count plurals · Possessive apostrophe · This and these
Third-person -s, past-tense forms and the base verb after do, did and modals. These are the endings that slip first under time pressure, and they are also the ones a careful listener or reader notices. Getting them automatic frees attention for ideas when you speak.
10 rules: Third-person present · Plural present be · Singular present have · Does plus base verb · Regular past events · Irregular past forms · Did plus base verb · Present progressive form · Modal plus base verb · Want plus to-infinitive
Questions turn normal word order around, and a few everyday patterns — there is, adjective before noun, at for clock times — have to be learned as units. Question order is a natural thing for Build a Sentence to check, and emails often need a well-formed direct question.
10 rules: Be in direct questions · Do with lexical verbs · Question-word order · Subject who questions · Not after an auxiliary · There is and there are · Adjective before noun · Adverb for manner · Listen to · At for clock time
Choosing between the simple past, the present perfect and the progressive tells the reader when something happened and whether it is finished. In an email explaining a problem, or a discussion post describing an experience, the wrong choice can blur the timeline.
10 rules: Habitual present · Progressive action now · Past action in progress · Present perfect form · Since a starting point · For a duration · Closed past time · Earlier of two past events · Used to for past habits · Future time clause
Because versus because of, although versus despite, who versus which: these words join ideas, and each needs a particular kind of phrase after it. They are central to developing a reason in the Academic Discussion task and to arranging longer sentences in Build a Sentence.
10 rules: Because plus clause · Because of plus noun phrase · Although without but · Despite plus noun phrase · Who for a person · Which or that for a thing · Whose for possession · Embedded question order · That-clause order · Future if-clause
Some verbs are followed by -ing, some by to, some by a bare verb; and the passive changes who appears as the subject. These patterns have to be learned verb by verb, and they show up constantly when you explain what someone decided, asked or allowed.
10 rules: Gerund after a preposition · Adjective plus infinitive · Enjoy plus gerund · Decide plus infinitive · Ask someone to act · Let plus base verb · Make plus base verb · Basic passive form · Passive agent by · Infinitive of purpose
Pronouns have to point clearly back to one thing, and comparisons need exactly one comparative marker. An unclear pronoun in particular can leave a sentence looking fine while making the reader stop and work out what you meant, which is costly in a short email or discussion post.
10 rules: Pronoun for one thing · Pronoun for a plural group · Clear pronoun reference · Single comparative marker · Single superlative marker · Than after a comparative · Fewer with count nouns · Less with noncount nouns · Ones for plural substitutes · Enough after an adjective
Reduced relative clauses, opening participles, appositives and inversion compress information into fewer words. Academic passages use them heavily, so recognizing them helps reading, and a few of them in your own writing can show range — as long as each one is correct.
10 rules: Active reduced relative · Passive reduced relative · Opening participle and subject · Noun clause as one subject · Appositive punctuation · Nonrestrictive which · Preposition before which · Subject relative pronoun · Whether-clause order · Negative-adverb inversion
Unreal conditions, past inferences with must have and may have, and wishes. These structures let you discuss what might happen or might have happened, which is exactly what interview questions about hypothetical situations ask for.
10 rules: Present unreal condition · Past unreal condition · Mixed past-to-present condition · Unless with future result · Must have for past inference · May have for past possibility · Should have for missed action · Wish about the present · Wish about the past · Would rather plus base verb
However, therefore, semicolons, colons and paired commas: the tools that connect sentences and show how ideas relate. They carry a discussion post from one point to the next, and their punctuation rules are strict enough to be worth learning precisely.
10 rules: However between clauses · Therefore between clauses · Semicolon and complete clauses · Colon after a complete clause · Paired commas in an aside · For example as a transition · Such as before examples · Whereas with clauses · This plus a summary noun · In addition to plus ing
Long subjects, each, a number of versus the number of, and items in a list that must match in form. These rules get harder as sentences get longer, which is why they matter most in academic writing and in longer Build a Sentence items.
10 rules: Intervening phrases · Each as subject · Subjects joined by and · Mixed subjects joined by nor · One of plus plural noun · A number of plus plural verb · The number of plus singular verb · No repeated relative subject · Parallel items in a list · Not only and but also
Work through the easy topics first, even if they look familiar. Cover each correct sentence and fix the trap yourself.
Keep a list of the traps you did not spot. These are your personal error patterns.
Before each practice email or discussion post, reread that list; after writing, proofread for those errors only.
Move to medium and hard topics as the easy traps become automatic.
See how grammar is weighed alongside content on the TOEFL Writing rubric, and pair this guide with word formation for the endings that change a word’s class.
Frequently Asked Questions
Not a separate one. Grammar is tested directly in Build a Sentence, where you arrange words into a correct sentence, and in Complete the Words, where word endings matter. It also affects how clearly your emails, discussion posts and spoken answers communicate.
Start with sentence structure, verb forms and question word order: they affect every task. Then move to clause connectors and agreement, which matter most in longer written responses.
No. ETS does not publish one. These 120 cards are original Test Ninjas teaching material, organized by difficulty and checked against the reference pages linked on each card.
Cover the correct sentence, read the trap, and fix it yourself before checking. Each trap is a typical learner error, so spotting them quickly is good practice for proofreading your own writing.