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.

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.

Past tense

• I walked home. — simple past (completed action)
• I was walking when it rained. — past progressive (in progress)
• I had already left when she arrived. — past perfect (earlier past)
• I had been waiting for an hour. — past perfect progressive (duration up to a past point)

Four past tense forms: simple past (done), past progressive (was happening), past perfect (had already happened), past perfect progressive (had been happening). Each encodes different timing relative to other past events.

Pattern: simple past = the story's main timeline. Past progressive = background action. Past perfect = flashback to something even earlier.

Present tense

• I work here. — simple present (habit/permanent)
• I am working now. — present progressive (happening right now)
• I have lived here for 10 years. — present perfect (started past, still true)
• I have been waiting for an hour. — present perfect progressive (duration up to now)

Four present tense forms: simple (habits/facts), progressive (now/temporary), perfect (past → present relevance), perfect progressive (ongoing duration). Each encodes a different relationship between the action and the present moment.

Trap: "I am living here for 10 years" ❌ — started in the past + still true = present PERFECT (have lived/have been living), not progressive.

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.

B2 | Upper Intermediate

• ✅ If I had studied harder, I would have passed. — third conditional
• ✅ The report is being reviewed by the committee. — passive progressive
• ✅ Having finished the exam, she left. — participle clause
• ✅ He denied having taken the money. — complex verb pattern

These are B2 patterns — the CEFR upper-intermediate level. At B2 you handle mixed conditionals, all passive forms, participle clauses, and can argue a point clearly. This is the level most universities and employers require.

Marker: if you can write a structured essay and debate an abstract topic, you're B2.

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.