Complete the hungry roommate's shocked complaint.
"You ate the last slice?! _____ the giant sticky note I left on the pizza box?"
The correct answer is Didn't you see.
We often use negative questions to express surprise or disbelief. When we use contractions, n't attaches to the auxiliary verb and comes before the subject (Didn't you see...?).
If we don't use a contraction, not must come after the subject (Did you not see...?), but the contracted form is much more common in conversation!
Questions
Questions in English are typically formed by inverting the subject and an auxiliary verb: She can dance → Can she dance?. When there's no auxiliary present, English adds do-support: The milk goes in the fridge → Does the milk go in the fridge?. The same pattern handles wh-questions (Where do you live?) and negative questions (Doesn't he know?).
The trickiest variant is indirect questions — I wonder where he is, not where is he. The inversion drops because the question is embedded inside another clause. Getting this right is one of the bigger jumps from A2 to B1 fluency.
Negation
Negation in English usually places not after the auxiliary or modal verb: I am not going, She does not know, You must not go. When there's no auxiliary, you add do-support: I go → I do not go. Most combinations contract: don't, can't, won't, isn't.
The trickiest rule for many learners: double negatives are not standard English. I didn't see nothing is non-standard; the standard forms are I saw nothing or I didn't see anything. Negative words like never, nobody, nothing already carry the negation — adding not on top doubles up.
Past tense
The past tense is how English talks about events finished before now. It comes in four flavours: simple past (I walked) for completed events, past progressive (I was walking) for actions ongoing at a past time, past perfect (I had walked) for events before another past event, and past perfect progressive (I had been walking) for ongoing events leading up to a past point.
Choosing the right one is what makes past narratives clear instead of murky. When I arrived, she ate dinner is technically grammatical but means something different than had eaten (already done) or was eating (in progress when you arrived).
Simple tense
The simple aspect is the unmarked verb form — no progressive -ing, no have + past participle. I go, I went, I will go are simple; I am going, I have gone, I had gone are not. The simple aspect typically marks a single completed action (Brutus killed Caesar), a repeated/habitual action (I go to school every day), or a permanent state (We live in Dallas).
The simple aspect is the foundation everything else builds on. Once it's automatic, switching into progressive (ongoing) or perfect (completed-relative-to-now) becomes a small adjustment rather than a fresh decision.
Auxiliary verb
An auxiliary verb (or "helping verb") is a verb that combines with a main verb to add grammatical meaning — questions, negation, tense, aspect, voice, or modality. The English auxiliaries are forms of be, have, do, plus the modal verbs (can, could, will, would, should, may, might, must).
Auxiliaries are what let you build past tense (have gone), continuous aspect (is going), passive voice (was eaten), and questions (Do you know?). Without them, you can't form most of the structures you need beyond the simple present and past — they're the engine that powers half the tense system.
B1 | Intermediate
B1 is the intermediate level in the CEFR framework — the point where you stop relying on memorised phrases and start handling everyday English independently. At B1 you can describe experiences, explain opinions, and follow most clear standard speech on familiar topics like work, travel, and hobbies.
Grammatically, B1 means combining tenses with precision, building complex sentences, and starting to use passive voice, modal verbs for necessity and possibility, and verb patterns (gerund vs. infinitive). Knowing your level shapes what you study next: pushing too far ahead frustrates you; staying below your level wastes time.
Difficulty: Medium
The Medium difficulty tag marks questions and challenges in the middle of the difficulty range — typically suitable for A2 to B1 learners. Expect a single rule with realistic distractors, longer sentences, and contexts where you have to think before answering rather than reading off the obvious choice.
Filter by Medium when you're past the absolute basics and ready to consolidate. It's the level where most lasting progress happens — easy enough that you can finish without exhausting concentration, hard enough that getting it right means you've actually understood.