Complement

Complement vs modifier: a complement is required — remove it and the sentence breaks (She is ___. / We consider him ___. ). A modifier is optional — remove it and the sentence still works (She spoke quietly → She spoke).

A complement completes the meaning of a verb or expression: subject complements follow linking verbs; object complements follow specific transitive verbs like call, elect, consider.

Diagnostic: can the verb survive without this element? No → complement. Yes → modifier or adjunct.

Subject

Subject vs object: the subject does or is; the object receives. She (subject) hit him (object). In English, position decides: subject comes before the verb, object after. Unlike inflected languages, English rarely marks subjects with case (exception: pronouns — I vs me).

The subject = who/what the sentence is about. Controls verb agreement. Usually a noun/pronoun before the verb.

Diagnostic: ask "who or what [verb]s?" The answer is the subject. The list of items is wrong — what is wrong? The list. That's your subject.

Object

Object vs subject: the subject does the action; the object receives it. The cat (subject) chased the mouse (object). In English, word order (SVO) determines which is which — subject before verb, object after.

An object is the entity a verb acts upon: direct (I read the book), indirect (I gave her a book), or prepositional (I waited for him).

Diagnostic: ask "[verb] what/whom?" after the verb. The answer is the direct object. Ask "to/for whom?" for the indirect object. After a preposition? Prepositional object.

Predicate

Subject vs predicate: every clause splits into two halves. Subject = who/what the sentence is about. Predicate = what's said about the subject (verb + objects + modifiers). The cat (subject) sat on the mat (predicate). Can't have one without the other in a complete sentence.

The predicate is the verb + everything attached to it. It contains the verb, objects, complements, and modifiers.

Diagnostic: find the main verb. The subject is to its left; the predicate starts at the verb and includes everything to its right. No verb = no predicate = fragment.

Preposition

Preposition vs particle: same words (in, on, up, off), different jobs. A preposition links to a noun (look at the book). A particle changes verb meaning without a noun (give up = quit). Test: is there a noun/pronoun after it forming a prepositional phrase? → preposition. Does it change the verb's meaning? → particle in a phrasal verb.

A preposition = small word connecting a noun to the sentence (time, place, manner, relationship). Choice is idiomatic per verb/adjective combination.

Diagnostic: struggling with which preposition to use? It's almost never about logic — look up the specific verb/adjective + preposition combination.

Pronoun

Pronoun vs noun: nouns name explicitly (Sarah, the book). Pronouns substitute and point back (she, it). Pronouns are a closed class (you can't invent new ones easily), while nouns are open (new ones appear constantly). The main complication: pronouns still carry case marking that nouns have lost.

A pronoun replaces a noun or noun phrase. Types: personal, demonstrative, relative, interrogative, reflexive, indefinite.

Diagnostic: every pronoun must have a clear antecedent (the noun it replaces). If the reader can't tell which noun a pronoun refers to → ambiguity error.

Adjunct

Adjunct vs argument: both add information to a clause, but arguments are required by the verb while adjuncts are optional. Remove an argument and the sentence breaks; remove an adjunct and it doesn't.

• She put the book on the table — on the table is an argument (put requires a location).
• She read the book on the table — on the table is an adjunct (optional where-info).

An adjunct is any element you can delete without making the sentence ungrammatical. Diagnostic: try removing the phrase — if the sentence still stands, it's an adjunct, not an argument.

Noun

Noun vs verb: the two core word classes. Nouns name things; verbs describe actions/states. Many English words can be both (run, play, cook, work) — only the sentence slot tells you which role it's playing. The run was exhausting (noun) vs I run every day (verb).

A noun names an entity. It interacts with articles, determiners, forms plurals, and controls verb agreement and pronoun choice.

Diagnostic: can you put the/a before it or pluralise it? → noun. Does it describe an action with tense? → verb. Can it do both? → check the sentence context.

Questions

Direct vs indirect questions: direct questions invert and end with ? (Where does she live?). Indirect questions DON'T invert and end with a period (I wonder where she lives.). Mixing these up — I wonder where does she live? ❌ — is one of the most common structural errors.

Questions in English use inversion/do-support. Types: yes/no, wh-, negative, tag. Direct questions invert; indirect don't.

Diagnostic: is your question embedded inside a statement (I wonder, Do you know, Can you tell me)? → DON'T invert. Is it a standalone question? → invert.

Auxiliary verb

Auxiliary vs main verb: a main verb carries the action (run, eat, think); an auxiliary verb carries the grammar — tense, negation, questions, aspect, voice. In She has been eating, eating is the main verb; has and been are auxiliaries.

The English auxiliaries are be, have, do (primary) and the modal verbs (can, will, must…). They always precede the main verb.

Diagnostic: can the word stand alone as the only verb in the sentence and still carry action? Yes → main verb. No → auxiliary.

Verb

Verb vs noun vs adjective: nouns name things. Adjectives describe. Verbs express what happens or what IS. The test: can it take tense (walked, will walk)? Can it take -ing? Can it follow to as an infinitive (to walk)? Yes to any → verb. English often converts freely between classes (run = noun or verb), so context decides.

A verb = action/state/occurrence word. 5 forms (base, -s, past, past participle, -ing). Carries tense, aspect, mood, voice. The one required element in every sentence.

Diagnostic: does it change for tense (walk → walked)? Can you put to before it (to walk)? Does it take -ing (walking)? → verb.

Negation

Single vs double negatives: standard English uses ONE negative per clause (I don't see anything or I see nothing). Double negatives (I don't see nothing) are grammatical in many languages and some English dialects, but are non-standard in written/formal English. This is the #1 negation trap for speakers of Spanish, Russian, and French.

Negation = not after auxiliary/modal, or do-support. Negative words (never, nobody, nothing) negate alone without adding not.

Diagnostic: count the negatives in the clause. More than one? → double negative. Fix by replacing one with a positive (anything, anyone, ever).

Complex sentence

Complex vs compound sentence: a compound sentence links two equal independent clauses with and/but/or. A complex sentence links an independent clause with a subordinate (dependent) clause — one idea is the main point, the other is background.

A complex sentence = independent clause + dependent clause. The dependent clause adds time (when), reason (because), condition (if), or detail (who/which).

Diagnostic: are both halves able to stand alone? Yes → compound. Can only one stand alone? → complex.

English Grammar Basics

Basics vs intermediate/advanced grammar: if you're unsure whether to study articles or conditionals, tense basics or reported speech — you need to check whether your foundations are solid first. Basics covers everything up to A2.

English Grammar Basics groups the core building blocks: nouns, verbs, adjectives, prepositions, present/past tenses, questions, and negation.

Diagnostic: if you still hesitate over she don't vs she doesn't, or a vs an — start here. Master these and intermediate topics stop feeling random.

A2 | Elementary | Pre-intermediate

A2 vs B1: A2 handles routine transactions and simple past narration. B1 handles connected discourse, explaining reasons, and understanding main points in clear standard speech. If you can tell what happened but not why it matters, you're still A2.

A2 is the elementary level of the CEFR: past simple, present perfect, first conditional, basic modals, and routine communication about familiar topics.

Diagnostic: can you link ideas with because, although, so that and hold a conversation beyond scripted topics? No → A2. Yes → moving into B1.

A1 | Elementary | Beginners

A1 vs A2: A1 covers isolated survival phrases (Where is…?, I am…, How much?). A2 handles connected sentences about familiar routines and simple past events. If you can manage short fixed phrases but not string together original sentences about your day, you're still A1.

A1 is the entry level of the CEFR: greetings, introductions, numbers, basic present tense, and core function words.

Diagnostic: can you describe yesterday using past tense? No → A1. Yes → you're moving into A2.

Easy

Easy vs Medium vs Hard: Easy = one rule, obvious answer, A1–A2. Medium = one rule but realistic distractors, A2–B1. Hard = interacting rules, edge cases, B2+. Start Easy to check you have the basics before moving up.

The Easy tag filters for single-rule, short-sentence, common-vocabulary challenges designed for beginners or for anyone wanting a confidence check on fundamentals.

Diagnostic: if you get Easy questions wrong, stay here — your foundations need work. If they feel trivial, move to Medium.