Interactive Grammar Reference & Exam
English has 12 tenses, which come from combining 3 times (past, present, future) with 4 aspects (simple, continuous, perfect, perfect continuous). This gives us 3 × 4 = 12 tenses.
Time tells us when an action occurs. Aspect tells us how the action relates to time — whether it is completed, in progress, or connected to another point in time.
Present Simple: used for habitual actions, general facts, and schedules. Form: subject + base verb (add -s/-es for third person singular).
Present Continuous: used for actions happening right now or temporary situations. Form: subject + am/is/are + -ing.
What is a participle? A participle is a verb form used to build tenses or act as an adjective. English has two types:
Present Perfect: used for past actions with present relevance, life experience, or actions in an unfinished time period. Form: subject + have/has + past participle.
Present Perfect Continuous: used for an action that started in the past and is still continuing, with emphasis on duration. Form: subject + have/has + been + -ing.
Past Simple: used for completed actions at a specific time in the past. Form: subject + past form (regular verbs add -ed).
Past Continuous: used for an action in progress at a specific past moment, or an action interrupted by another. Form: subject + was/were + -ing.
Past Perfect: used for an action completed before another past action. Form: subject + had + past participle.
Past Perfect Continuous: used for an ongoing action that was in progress before another past event, with emphasis on duration. Form: subject + had + been + -ing.
Future Simple (will): used for predictions, spontaneous decisions, and promises. Form: subject + will + base verb.
Future Continuous: used for an action that will be in progress at a specific future moment. Form: subject + will + be + -ing.
Future Perfect: used for an action that will be completed before a specific future point. Form: subject + will + have + past participle.
Future Perfect Continuous: used for an ongoing action that will have been in progress up to a specific future point. Form: subject + will + have + been + -ing.
Time markers help identify which tense to use:
Click each word or phrase to reveal its grammatical role in the sentence.
1. “She ___ English every day.” — which tense?
2. “I have been waiting for two hours.” — which tense?
3. “By next year, she will have graduated.” — which tense?
Conditionals express “if…then” relationships between two events or situations. Every conditional sentence has two parts: the if-clause (the condition) and the result clause (the consequence).
The type of conditional depends on how probable or real the situation is — ranging from universal facts to impossible past events.
The zero conditional describes things that are always true: scientific facts, general laws, and things that happen every time the condition is met.
Form: If + present simple, present simple
Both clauses use the present simple because the relationship is universally and permanently true. You can swap the clauses without changing the meaning.
The first conditional describes real and likely future situations — things that may genuinely happen.
Form: If + present simple, will + base verb
Note: the if-clause uses present simple (not “will”). “If it will rain” is incorrect.
The second conditional describes unreal, imaginary, or unlikely present or future situations.
Form: If + past simple, would + base verb
In formal English, “were” is used for all persons in the if-clause (“If I were…”, “If she were…”). This is the subjunctive form.
The third conditional describes situations that are impossible to change — imagining a different outcome for something that already happened in the past.
Form: If + past perfect, would + have + past participle
The third conditional is often used to express regrets or to imagine how things could have been different. The past is fixed; this is purely hypothetical.
Mixed conditionals combine elements from different conditional types, mixing time frames between the if-clause and the result clause.
Click each word or phrase to reveal its grammatical role in the sentence.
1. “If I won the lottery, I would travel.” — which conditional?
2. “If you heat ice, it melts.” — which conditional?
3. “If she had known, she would have helped.” — which conditional?
A noun names a person, place, thing, idea, or feeling. Nouns can be common (teacher, city, phone) or proper (Naree, Bangkok, Samsung — always capitalised).
Nouns fall into several useful sub-groups:
An adjective describes or modifies a noun. In English, adjectives usually come before the noun, or after a linking verb like be, seem, look.
-ed vs -ing adjectives. Both come from verbs, but they mean very different things:
Order of adjectives. When several adjectives come before one noun, English follows a rough order: opinion → size → age → shape → colour → origin → material.
An adverb adds information about a verb, an adjective, or another adverb — answering how? when? where? how often? how much? Many adverbs end in -ly, but not all (fast, well, hard, often).
Adjectives and many adverbs have three degrees: positive (tall), comparative (taller), superlative (tallest).
To compare two things use than. To name the top of a group use the + superlative.
1. Which word is an abstract noun?
2. “The football match was very ___.”
3. “Her painting is ___ than mine.”
Countable nouns name things you can count separately — they have singular and plural forms. You can put a number or a/an in front of them.
Use many, few, or several with plural countable nouns.
Uncountable nouns name substances, liquids, ideas, or groups of things seen as a mass. They have no plural form and take a singular verb.
Use much, little, or a lot of with uncountables. To count them, use a container or unit: two cups of coffee, a piece of advice, three pieces of furniture.
A gerund is the -ing form of a verb used as a noun. It can be the subject, object, or follow a preposition.
The infinitive has two forms: the to-infinitive (“to go”) and the bare infinitive (“go”, without “to”).
Some verbs are always followed by a gerund, some by an infinitive, and some by either. There is no single rule — you must memorise the common ones.
1. Which sentence is correct?
2. Choose the correct form: “I enjoy ___.”
3. “She can ___ three languages.”
Modal verbs add meaning to a main verb — about ability, permission, obligation, likelihood, or advice. The English modals are:
Modals follow three rules that make them easy to recognise:
can = present ability • could = past or general ability • be able to fills the gaps where modals can’t go.
From informal to formal: can → could → may.
Modals express how sure the speaker is. From least to most certain:
To speak about the past, use modal + have + past participle.
1. Which sentence is correct?
2. “You ___ wear a uniform at this school — it’s optional.”
3. “I forgot her birthday. I ___ called her.”
A preposition is a short word that shows the relationship between a noun (or pronoun) and another word in the sentence — usually in terms of place, time, direction, or cause.
A preposition is almost always followed by a noun, noun phrase, or pronoun. This group of words is called a prepositional phrase.
Some prepositions are made of two or three words acting as one. Common examples:
Many adjectives and verbs are followed by a specific preposition. These pairings must be learned together:
The same little word can be a preposition (part of a prepositional phrase) or a particle (part of a phrasal verb). The way to tell: a preposition introduces a noun; a particle changes the meaning of the verb.
1. “The meeting starts ___ 9 a.m.”
2. “She’s afraid ___ spiders.”
3. In “Please look up the word”, ‘up’ is:
A pronoun is a word that replaces a noun so we don’t have to repeat it. Instead of “Naree gave Naree’s book to Niran”, we say “She gave her book to him.”
Subject pronouns do the action: I, you, he, she, it, we, they.
Object pronouns receive the action (or follow a preposition): me, you, him, her, it, us, them.
This is where many learners slip up.
this, that, these, those point to things in space or time.
Reflexive pronouns end in -self or -selves: myself, yourself, himself, herself, itself, ourselves, yourselves, themselves. Use them when the subject and the object are the same person.
Indefinite pronouns refer to non-specific people or things: someone, anyone, everyone, nobody, something, anything, everything, nothing, all, each, few, many, several.
Most are grammatically singular and take a singular verb:
1. “Come with ___.”
2. “Whose pen is this?” — “It’s ___.”
3. “The cat licked ___ paws.”
A phrasal verb is a verb combined with one or two little words (a particle) whose meaning is often very different from the verb alone.
In separable phrasal verbs, the object can go between the verb and the particle, OR after the particle:
With a pronoun object, it must go between the verb and the particle:
Inseparable phrasal verbs cannot be split. The object always follows the whole phrase:
Stative verbs describe states, feelings, or relationships — things that don’t change moment-to-moment. They are normally not used in continuous (-ing) tenses.
Dynamic verbs describe actions or processes you can see happening: run, write, build, travel, eat. They can be used in any tense, simple or continuous.
Some verbs can be both stative and dynamic — the meaning changes with the form.
1. Which sentence is correct?
2. Which is correct?
3. “I’m ___ dinner right now — can I call you later?”
A transitive verb passes its action onto an object. Ask “what?” or “whom?” after the verb — if there’s an answer in the sentence, the verb is transitive.
Only transitive verbs can be made passive: “A book was bought (by her).”
An intransitive verb does not take a direct object. The action stops at the subject.
Intransitive verbs cannot be made passive. Common intransitives: arrive, come, go, happen, die, sleep, exist, rise.
Many English verbs are ambitransitive — they can be transitive or intransitive depending on context.
Watch out for tricky pairs where one is transitive and one isn’t:
Conjunctions connect words, phrases, or clauses. English has three main types.
Seven short words connect equal parts of a sentence: For, And, Nor, But, Or, Yet, So. Use a comma before FANBOYS when they join two full (independent) clauses.
These introduce a dependent clause — a clause that cannot stand alone. Common ones:
These work as a team: both…and, either…or, neither…nor, not only…but also, whether…or.
1. Which verb is intransitive (takes no direct object)?
2. “___ it was raining, we went for a walk.”
3. Complete the correlative pair: “Neither rain ___ snow stopped us.”
A verb describes an action, state, or occurrence. A sentence in English must contain a verb.
The subject of a verb is the performer of the action. The object is the target of the action.
1. In “Shouvik plays the piano”, what is ‘the piano’?
2. Which is a dependent clause?
3. What is the difference between a phrase and a clause?
In active voice, the subject performs the action.
Form: Subject + Verb + Object
Most English sentences use active voice — it is direct and clear.
In passive voice, the subject receives the action.
Form: Subject + be (conjugated) + past participle (+ by agent)
The agent (doer) can be omitted when unknown or unimportant:
Use passive voice when:
The passive works in all tenses — only the form of be changes:
Only transitive verbs (verbs that take a direct object — see Unit 9) can be made passive. Intransitive verbs like sleep, arrive, and cry have no object, so there is nothing to become the passive subject.
Some passives are grammatically correct but sound awkward in practice:
Click each word or phrase to reveal its grammatical role in the sentence.
1. Which sentence is in the passive voice?
2. Why can’t “The baby cried” be made passive?
3. “The report ___ written by the manager.” — Fill in the correct form of be:
Articles are determiners that come before nouns. English has three articles — a, an, the — plus the concept of the zero article (using no article at all). Articles are one of the most challenging grammar areas for ESL learners, because many languages do not have a direct equivalent.
Use a or an with singular countable nouns that are mentioned for the first time, or when speaking about one of many (not a specific one).
Cannot be used with uncountable nouns or plurals: NOT “a water”, NOT “a books”.
Use the when both the speaker and listener know which specific thing is meant. Use it in these situations:
Use no article in these common cases:
Click each word to identify its grammatical role in these sentences.
Sentence 1:
Sentence 2:
1. “___ honest person” — which article is correct?
2. “___ water is essential for life” (general statement) — which is correct?
3. “She plays ___ piano beautifully.” — which is correct?
Sentence diagrams break a sentence into its structural components, showing how words relate to each other. This is one of the most valuable tools for understanding grammar.
Every sentence has a subject (who/what performs the action) and a predicate (what is said about the subject). The predicate contains the verb and often a direct object.
The vertical line separates subject from predicate. The shorter line before the object does not cut through the baseline — the object belongs to the predicate.
Adjectives modify nouns and sit on slanted lines below them. Adverbs modify verbs, adjectives, or other adverbs and also sit on slanted lines.
A prepositional phrase = preposition + noun phrase. It modifies a noun (acting as an adjective) or a verb (acting as an adverb). In diagrams, the preposition sits on a slanted line connecting to a horizontal line holding its object.
A clause is a group of words containing a subject and a verb.
A phrase is a group of words that does not contain both a subject and a verb acting together. A clause does.
Click on the words below to see their grammatical role highlighted:
1. In a sentence diagram, what separates the subject from the predicate?
2. Where do adjectives appear in a sentence diagram?
3. How are prepositional phrases shown in a sentence diagram?
Every sentence can be divided into two parts: the subject (who or what the sentence is about) and the predicate (everything said about the subject). The predicate always contains the verb.
The simple predicate is just the main verb (or verb phrase). The complete predicate is the verb plus all its modifiers, objects, and complements.
A compound predicate contains two or more verbs that share the same subject, joined by a conjunction.
After a linking verb (be, seem, become, appear, feel, look, taste, etc.), the predicate contains a complement that describes or renames the subject:
To find the predicate, first find the subject, then everything else is the predicate:
1. What is the predicate of a sentence?
2. In “She has been reading all morning”, what is the simple predicate?
3. In “The cake tastes delicious”, ‘delicious’ is a:
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