"Hey, I have a huge chemistry exam tomorrow morning. Would you mind turning down that aggressive accordion music? Also, could you use headphones next time you practice?"
When we make a polite request using "Would you mind...", it must be followed by a gerund (the -ing form of the verb).
When we make a request with "Could you...", it is followed by the base form of the verb (without "to").
Modal verb
Must vs should vs might: the most confused modal trio. Must = strong obligation/near-certainty. Should = advice/expectation. Might = possibility. Getting these wrong changes the force of your statement: You must see a doctor (urgent) vs You should see a doctor (advice) vs You might need a doctor (maybe).
Modal verbs are auxiliaries that encode modality: ability (can), permission (may), necessity (must), advice (should), possibility (might), future (will).
Diagnostic: what meaning are you adding? Obligation → must/have to. Advice → should. Possibility → might/could. Ability → can. Future → will.
Gerund
Gerund vs infinitive: the biggest source of errors for non-native speakers. Some verbs take only gerund (enjoy reading ✅), some only infinitive (want to read ✅), some take both with different meanings (stop reading ≠ stop to read). There's no logical rule — these must be learned by verb.
A gerund is the -ing verb form used as a noun. After prepositions = always gerund. After certain verbs (enjoy, avoid, finish) = always gerund. After to (preposition, not infinitive marker) = gerund (I look forward to seeing you).
Diagnostic: can you replace the -ing word with "it" or "something"? I enjoy it → yes, it's acting as a noun = gerund.
English grammar
Grammar vs vocabulary: vocabulary gives you the words; grammar gives you the system for combining them into meaning. Knowing 10,000 words without grammar produces incoherent sentences. Knowing grammar with limited vocabulary produces clear, correct sentences about fewer topics. Both matter — but grammar is the framework.
English grammar is the complete rule system: parts of speech, phrase and sentence structure, tenses, agreement, word order, and punctuation.
Diagnostic: if your sentences are understood but "sound wrong" → grammar issue. If you can't find the right word → vocabulary issue. If both → start with grammar.
Infinitive
Infinitive vs gerund: the #1 verb-pattern confusion. Some verbs take only infinitive (want to go ✅), some only gerund (enjoy going ✅), some both with different meanings (stop to smoke ≠ stop smoking). No logical rule exists — learn by verb.
The infinitive = base verb form used non-finitely. To-infinitive (to go) after certain verbs. Bare infinitive (go) after modals and causatives.
Diagnostic: what's the main verb? Check whether it takes to-infinitive, bare infinitive, or gerund. If unsure, try both and see which sounds natural to native speakers.
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.
Phrasal verb
Phrasal verb vs verb + preposition: a phrasal verb has a non-literal combined meaning (run into = meet by chance). A verb + preposition keeps its literal meaning (run into the room = physically run inside). The test: is the meaning predictable from the parts? No → phrasal verb. Yes → just a verb followed by a preposition.
Phrasal verbs combine verbs with particles/prepositions to create new meanings. They're the single biggest gap between textbook English and real native usage.
Diagnostic: can you guess the meaning from the individual words? No → phrasal verb (learn as unit). Yes → literal verb + preposition.
Humor
Humor vs serious practice: both teach the same rules. The difference is engagement — funny material keeps you coming back and creates stronger memory hooks. If dry drills bore you into quitting, humorous practice is more effective because you actually do it.
The Humor tag filters for entertaining practice: silly contexts, wordplay, absurd examples — all testing real grammar rules underneath.
Diagnostic: if you find yourself dreading practice → try filtering by Humor. If you're preparing for a formal exam and want serious register → filter it out.
B1 | Intermediate
B1 vs B2: B1 handles standard everyday communication and simple opinions. B2 handles abstract topics, sustained arguments, and nuanced register. If you can chat about your life but struggle to debate an issue or write a formal essay, you're B1.
B1 is the intermediate CEFR level: independent handling of familiar topics, second conditional, basic passive, reported speech, and linking words for cause and contrast.
Diagnostic: can you read a newspaper article on a familiar topic and summarise the argument? Comfortably → B2. Struggle with abstractions → still B1.
Medium
Medium vs Easy: Easy has one obviously correct answer and clearly wrong distractors. Medium has one correct answer but plausible distractors — you need to actually know the rule, not just guess from sound.
The Medium tag filters for A2–B1 challenges with realistic difficulty: one rule per question, plausible alternatives, everyday contexts.
Diagnostic: if you're scoring 90%+ on Easy, move here. If you're below 60% on Medium, go back to Easy for that topic. Target 70–80% accuracy for maximum learning.