Choose the correct phrase to complete the sentence.
It's Saturday — no school today! You ___ wake up early. You can sleep in! 🎉
The correct answer is don't have to.
"Don't have to" means there is no obligation — it is not necessary. Since there is no school on Saturday, waking up early is not required (but you still can if you want 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.
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).
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.
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.
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.