The correct answers are on, in, and at.
We use on for surfaces of a building (like on the roof or on the ceiling).
We use in for enclosed rooms and spaces inside a building (like in a hotel room).
We use at for a building when we think about the activity that happens there or use it as a general meeting point (like at the theater or at the cinema).
Preposition
- ✅ interested in — ❌ interested on
- ✅ good at football — ❌ good in football
- ✅ depend on — ❌ depend of
- ✅ arrive at the station — ❌ arrive to the station
Prepositions link nouns to the rest of the sentence: time (at 5pm), place (in London), manner (with care), abstract (afraid of). Most are idiomatic — the "correct" preposition must be memorised with each verb/adjective combination.
Rule: there is no universal rule. English prepositions are learned by combination: interested IN, good AT, depend ON, afraid OF. Your native language's equivalent will often mislead.
A1 | Elementary | Beginners
- ✅ My name is Anna. — present simple of be
- ✅ Where is the station? — basic *wh-*question
- ✅ I have two brothers. — possession with have
- ✅ She likes coffee. — third-person -s
These are A1 sentences — the starting level of the CEFR framework. At A1 you can introduce yourself, ask and answer simple personal questions, and handle basic everyday transactions using present tense, be/have/do, and core vocabulary.
If you can say these but freeze at normal speaking speed, you're solidly A1 — and that's exactly where to start.
Medium
- If I were you, I would apologise. — one rule (second conditional), but distractors like was tempt you
- Answers require active thought, not instant pattern recognition
- Vocabulary and context are realistic, not artificially simplified
- Usually tests one rule, but the wrong answers are plausible
Medium marks middle-difficulty challenges: A2–B1, one rule tested, but with realistic distractors that require genuine understanding.
Use "Medium" when Easy feels too obvious but Hard feels overwhelming. This is where most productive learning happens — the sweet spot of difficulty.