The correct prepositions are on, on, to, and in.
We say insist on doing something. Things depend on other things (never depend of or depend from). You object to an idea or action. You believe in something when you trust its value or existence.
English grammar
If you can speak English but feel you're forever guessing — should that be a/the?, would have been or had been?, who or whom? — you don't have a vocabulary problem; you have a grammar problem. Grammar is the system that turns isolated words into precise meaning, and the only difference between guessing and knowing is studying it deliberately.
English grammar is the system of rules that govern how meanings are encoded in English: word formation, phrase and sentence structure, tenses, agreement, word order, and punctuation.
Preposition
If you've ever written I'm interested on you (should be in) or I'm good on football (should be at) — you've hit prepositions' main pitfall. Their choice is mostly idiomatic, not logical, and rarely matches what your native language does. Memorising the right preposition for each common verb and adjective is what stops your speech from sounding subtly off.
A preposition is a small word linking a noun or noun phrase to other parts of the sentence: in, on, at, to, from, with. Marks time, place, manner, or abstract relationships. Choice is largely idiomatic, especially in fixed combinations (depend on, good at, afraid of).
Verb
If grammar feels overwhelming, the fix is almost always to focus on verbs first. They carry the action, the time, the mood, and the voice — a single verb form decides whether your sentence reads as past or present, fact or hypothetical, active or passive. Get verbs solid and the rest of grammar suddenly looks much smaller.
A verb expresses action, state, or occurrence — the engine of every English sentence. Most verbs have five forms (base, -s, past tense, past participle, -ing); be has eight; modal verbs have fewer. Verbs carry tense, aspect, mood, and voice.
Collocations
If your English vocabulary is large but your speech still sounds slightly off — do a mistake, powerful coffee, high winds blew strongly — you've hit the collocation problem. Each word is correct in isolation, but native speakers don't pair them that way. Fixing it isn't about more vocabulary; it's about learning words in their natural company.
Collocations are word combinations that habitually occur together: make a decision, strong coffee, heavy rain, highly unlikely. The grammar permits other pairings, but fluent English consistently chooses one over the rest. They're the connective tissue of natural-sounding language.
Humor
If you've ever reached the third drill of present perfect and felt your eyes glaze over, you've hit the limits of dry repetition. Practice that's even mildly funny is far easier to come back to — and far easier to remember weeks later. That's the whole point of the Humor tag.
The Humor tag marks questions where the author has tried to make the practice entertaining alongside instructive. Subjective, sometimes silly, but designed to keep you engaged long enough for the rule to stick.
B2 | Upper Intermediate
If a university admissions team or visa office has ever asked you for an English test score, B2 is probably the level they had in mind. It's the threshold where your English stops being a constraint and starts being a tool — and the line between B1 and B2 is often the line between "stuck in beginner classes" and "ready to study or work in English."
B2 is the upper-intermediate level in the CEFR framework, demanding flexible control of mixed conditionals, passive voice across tenses, reported speech with backshifting, and participle clauses.
Difficulty: Medium
If easy questions feel too obvious but hard questions leave you guessing, you're probably ready for Medium — the level where most real learning happens. It pushes just enough to expose the rules you don't quite have yet, without burying you in edge cases. This is where steady fluency is built, one well-aimed challenge at a time.
The Medium difficulty tag marks middle-range challenges — typically A2 to B1. One rule per question, realistic distractors, and contexts that require active thought rather than instant recognition.