Conditional sentence

• ✅ If you heat ice, it melts. — zero conditional (always true)
• ✅ If it rains, I*'ll** take an umbrella.* — first conditional (real future)
• ✅ If I had wings, I would fly. — second conditional (unreal present)
• ✅ If I had left earlier, I would have caught the train. — third conditional (unreal past)

Conditional sentences pair an if-clause with a consequence. Five patterns (zero through mixed) each combine specific tenses to express different levels of reality and time.

Pattern: the tense in the if-clause is always one step "back" from what you'd expect — past for present hypotheticals, past perfect for past hypotheticals.

Inversion

• ✅ Has Sam read it? — question inversion (basic)
• ✅ Rarely have I seen such talent. — fronted negative (advanced)
• ✅ Not only does she sing, she also writes. — correlative inversion
• ✅ Had I known, I would have acted. — inverted conditional (no if)

Inversion = subject and auxiliary swap places. Basic: all English questions. Advanced: fronted negatives/restrictives (Rarely…, Not only…, Never…) and formal conditionals without if.

Pattern: put a negative/restrictive adverb at the front → invert subject and auxiliary. This is a C1+ rhetorical device for emphasis.

Verb tense

Verb tense = time (past/present/future) × aspect (simple/progressive/perfect) = 12 forms. Each slot has a specific job — not just "when" but "how the action relates to its time frame."

Key insight: most learners don't need all 12 at once. Simple covers 80% of communication. Add perfect and progressive as needed.

Subjunctive mood

• ✅ If I were you… — past subjunctive (not was)
• ✅ I suggest that he go. — present subjunctive (not goes)
• ✅ It's important that she be present. — present subjunctive
• ❌ If I was you… — common in speech, avoided in formal writing

The subjunctive uses bare-infinitive forms (go, be) after verbs of demand/suggestion, and were (not was) in unreal/hypothetical conditions. Two contexts: that-clauses (I insist that he leave) and if-clauses (If she were here).

Rule: after suggest/recommend/demand/insist that… → use base form. In if + unreal condition → use were for all persons.

Negation

• ✅ I don't see anything. — ❌ I don't see nothing. (double negative in standard English)
• ✅ She never goes out. — never already negates (no doesn't needed)
• ✅ He doesn't like coffee. — do-support for negation
• ✅ Nobody came. — negative subject (no auxiliary needed)

Negation uses not after an auxiliary/modal, or do-support when there's no auxiliary. One negative per clause in standard English — never, nobody, nothing already negate without adding not.

Rule: one negative element per clause. I don't see anything or I see nothing — never both together in standard English.

C1 | Advanced

• ✅ Not only did she finish early, but she also helped others. — inversion for emphasis
• ✅ It is the process that matters, not the result. — cleft sentence
• ✅ I insist that he be present. — formal subjunctive
• ✅ Were I to disagree, I would say so. — inverted conditional

These are C1 structures — the CEFR advanced level. At C1 you control inversion, cleft sentences, subjunctive forms, and register-switching fluently across formal and informal contexts.

Marker: if you can restructure a sentence for rhetorical effect without hesitation, you're C1.

Hard

• Had she not intervened, the situation would have escalated. — inverted conditional
• All distractors are grammatically plausible in other contexts
• Multiple rules interact (e.g., tense + aspect + modality)
• Context determines the answer — no single "rule" is enough

Hard marks upper-intermediate to advanced challenges: B2+, interacting rules, edge cases, plausible distractors, and contexts where pattern-matching fails.

Use "Hard" when Easy/Medium feel trivial and you want to test whether you actually understand a rule versus just recognising surface patterns.