The correct answers are were it not for and if it were not for.
If it were not for is a fixed conditional phrase used to say that someone or something prevents a hypothetical situation from happening. Because it is an unreal situation, it uses the subjunctive were.
Just like other "were" conditionals, you can invert it by dropping "if": Were it not for.
"Was it not for" is grammatically incorrect because conditional inversion strictly requires the subjunctive "were."
Subjunctive mood
If you've heard if I were you and wondered why it's not if I was you — you've met the past subjunctive. English barely marks the subjunctive anymore, but in formal writing and a few stock phrases, getting it right (or wrong) is one of the clearest signals of a careful writer. I demand that he be present. / If I were richer. — both subjunctive, both reading as wrong if you swap them out.
The subjunctive mood marks hypothetical or counterfactual contexts. Two main forms: present subjunctive in that-clauses after verbs of recommendation (I suggest that he go) and past subjunctive were in unreal conditionals (If I were you). Mostly invisible in modern English, but unmistakable when present.
Conditional sentence
Want to say I would have caught the train if I'd left earlier without freezing on the verb forms? That's a third conditional, and it's one of five patterns English uses to talk about possibilities, regrets, and hypotheticals. Get the system right and you stop sounding stuck in the present tense.
A conditional sentence pairs a condition clause (usually with if) with a consequence clause: If it rains, we stay in. The five named patterns — zero, first, second, third, and mixed — each match a specific time frame and likelihood, with their own tense rules.
Inversion
If you've ever read Rarely have I seen such talent in a book or speech and wondered why the verb came before the subject — you've met inversion's literary form. It's the same machinery English uses for questions (Has Sam read it?) but applied to declarative sentences for emphasis. Mastering it is the difference between flat formal writing and prose that lands.
Inversion swaps the normal subject + verb order. The basic case is questions: Has Sam read it?. The advanced case is fronted negatives and restrictives: Rarely have I seen such dedication; Not only does she sing, she also writes. The latter is a C1+ feature.
Verb mood
If grammar references confuse you with terms like "subjunctive" or "conditional" — and you've never quite understood why English needs them — you've hit the verb-mood layer. Each mood marks a different attitude: fact vs command vs hypothetical vs polite recommendation. Once that map is clear, structures like if I were you or I suggest he go stop looking like exceptions and start looking like a system.
Verb mood signals the speaker's attitude toward the action. The four English moods: indicative (facts), imperative (commands), subjunctive (hypotheticals, formal recommendations), and conditional (would/could constructions).
Idiom
If you've ever heard a native speaker say that's a piece of cake and wondered what cake had to do with anything — you've met your first idiom. English films, songs, and casual chat are full of these fixed expressions, and missing them leaves the meaning slightly off-kilter. Learning idioms in chunks is the fastest way to stop sounding overly formal.
An idiom is a fixed phrase whose meaning isn't built from its individual words. Kick the bucket (= to die), spill the beans (= reveal a secret), break a leg (= good luck). They have to be memorised as whole units; word-by-word translation almost always misleads.
C1 | Advanced
If you've ever sat through a lecture in English, written a complaint letter, or argued a point in a meeting and come out feeling actually understood — not just tolerated — you've felt what C1 looks like. The level matters because it's where most universities, certifications, and skilled-work environments draw their language line.
C1 is the advanced level in the CEFR framework, demanding fluent and flexible language: inversion for emphasis, mixed and advanced conditionals, formal subjunctive, cleft sentences, and complex nominal phrases — all used appropriately across registers.
Difficulty: Hard
If easy and medium questions are clicking but you still feel exposed in real conversation or formal writing, you've outgrown the basics. Hard material is where the gaps you didn't know you had show up: the distractor that "sounds right", the rule that interacts with another rule, the case where context changes the answer. It's where genuine fluency is built.
The Hard difficulty tag marks upper-intermediate to advanced challenges — typically B2 and above. Interacting rules, edge cases, plausible distractors, and contexts that require genuine understanding rather than surface pattern-matching.