The correct answers are: I have worked the night shift since 1897. I have been unemployed for two centuries. I last saw the sun over four hundred years ago.
Since pairs perfectly with specific points in time, like a specific year (since 1897).
For requires a duration of time, like two centuries or a long time. You cannot say "since a long time" or "for 1897".
Ago is placed after a period of time to indicate a point in the past (four hundred years ago).
Preposition
A preposition is a small word that links a noun or noun phrase to other parts of the sentence — usually marking time, place, or relationship: in, on, at, to, from, with, over, under, between, during. The book on the table, We met at noon, She lives in Berlin.
Prepositions are deceptively small. Their meaning shifts dramatically by collocation (depend on, good at, afraid of), and their choice rarely translates directly between languages. Picking the right preposition is one of the trickiest, most idiomatic-sounding parts of English.
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).
English Grammar Basics
The English Grammar Basics tag marks quizzes and explainers covering the foundations of English grammar — nouns, verbs, adjectives, adverbs, prepositions, conjunctions, tenses, voice, mood, and basic sentence structure.
If you're starting out or rebuilding from scratch, this is the tag to follow: every challenge under it is designed to land the core rules without burying you in exceptions. Get the basics solid here and the more advanced topics — conditionals, reported speech, inversion — stop looking like a wall of new rules and start looking like extensions of what you already know.
Humor
The Humor tag marks questions and challenges where the author has tried — subjectively, deliberately — to make the practice itself entertaining. Expect characters, scenarios, and storylines that play with absurdity: zombies, alien tourists, a chef's disaster, a roommate's complaint. The grammar rule is real; the wrapping isn't.
Humor matters because grammar drills are forgettable. Tying a rule to a story your brain wants to keep makes it stick. Filter by Humor when motivation is what you're short on, not study time.
A2 | Elementary | Pre-intermediate
A2 is the elementary level in the CEFR framework, sitting between A1 and B1. At A2 you can handle routine exchanges — ordering food, asking directions, making small talk — and describe your immediate environment in simple sentences.
Grammatically, A2 introduces past simple and past continuous, present perfect for experiences, basic modal verbs, and the first conditional. You're also picking up collocations and learning which verbs take gerunds vs. infinitives. Knowing your level here is the difference between confident progress and frustration: A2 material consolidates the basics; B1 will overwhelm you.
Difficulty: Easy
The Easy difficulty tag marks questions and challenges aimed at beginners — typically A1 or early A2 level. Expect single-rule focus, short sentences, common everyday vocabulary, and one clear correct answer. Distractors usually rule themselves out quickly.
Filter by Easy when you're rebuilding fundamentals, warming up before harder material, or testing whether you've truly internalised a basic rule before moving on. Easy doesn't mean trivial — it means the rule itself is unambiguous and the context doesn't pile on extra complications.