For vs Since Exercises: 25 Questions With Instant Answers

For and since both talk about time that started in the past and continues to now, and both live in the same tense — the present perfect. The difference is what follows them: for measures how long (a duration: for ten minutes, for six months, for a long time), while since marks when it started (a starting point: since 9 a.m., since March, since we met).

The 25 sentences below go from warm-up to challenge and include the classic traps: for with a clause, since in negative sentences, all day without either word, and the tense choice that pairs with each. Every answer is checked on the spot with a one-line explanation, so each miss teaches the rule instead of just the answer.

The One Rule: Duration vs Starting Point

Every for/since question reduces to a single test: does the phrase after the gap measure how long (a duration) or mark when it began (a starting point)? Durations take for — for ten minutes, for three weeks, for years, for a long time. Starting points take since — since 8 o'clock, since May, since 2015, since the meeting, since we moved.

Why For and Since Live With the Present Perfect

For and since connect the past to the present, which is exactly the job of the present perfect: I have lived here since 2020 (and still do). If the situation is finished, English switches to past simple and drops since entirely: I lived there for five years (but not anymore), or I lived there from 2015 to 2020.

This is the single most common error with this pair — using present simple instead of present perfect. I live here since 2020, she works here for five years, and we are married since June all sound wrong to native ears because the present simple cannot look backward.

Five Mistakes That Give You Away

Beyond the tense error, for and since attract a short list of recurring mistakes. Most come from direct translation: many languages use one word for both ideas (Spanish desde, French depuis, Japanese 〜から, Arabic منذ), so the duration/point split has to be learned fresh.

Since as a Conjunction — and the Meaning Shift

Since does double duty in English: besides marking a starting point, it can mean because (since you're here, let's start). The time sense pairs with the present perfect in the main clause; the because sense pairs with any tense and usually opens the sentence.

For has its own double duty too — as a conjunction meaning because (formal/literary: for it was already late). In modern writing that use is rare; when you see for as a preposition of time, it is the duration sense nine times out of ten.

How to Practice For and Since Until It's Automatic

Do one 25-question set like the one above, then make the pattern personal: write five true sentences about your own life — how long you have studied English, lived in your city, known your best friend, worked at your job, owned your phone. Each sentence forces the duration/point decision with real stakes, which is how the rule moves from knowledge to reflex.

Then check your own writing. Paste those sentences (or any email) into PromGee's free grammar checker: it flags the wrong preposition and the wrong tense together, and explains the rule in your language.

Frequently Asked Questions