Complete the detective's frustrated case notes by dragging the correct words into the blanks.
We could have caught the phantom thief if we had noticed those muddy footprints earlier.
We could have caught the phantom thief if we had noticed those muddy footprints earlier.
The third conditional can use modal verbs like could or might instead of would to show possibility in the hypothetical past.
The main clause uses could have + past participle (caught).
The "if" clause uses the past perfect (had noticed) because it refers to a missed opportunity in the past.
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.
Modal verb
- ✅ She can swim. — ❌ She can to swim. (modal + bare infinitive, no to)
- ✅ You must leave now. — strong obligation
- ✅ It might rain. — possibility (~50%)
- ✅ He should apologise. — advice/recommendation
Modal verbs (can, could, may, might, must, shall, should, will, would) are auxiliaries expressing ability, permission, possibility, obligation, or speculation. Always + bare infinitive. Never inflected (she can, not she cans).
Rule: modals never take to after them, never add -s for third person, and can't combine directly (must can ❌ — use must be able to).
Perfect tense
- ✅ I have lived here for ten years. — present perfect (started past, still true)
- ❌ I live here for ten years. — wrong (simple present can't bridge past→now)
- ✅ She had finished before I arrived. — past perfect (earlier past)
- ✅ They will have left by noon. — future perfect (completed before future point)
The perfect = have + past participle. Connects an action to a reference point in time. Present perfect bridges past→now. Past perfect marks "earlier past." Future perfect marks "done before a future deadline."
Rule: if the action started in the past and is still relevant now → present perfect (have done). If two past events and you need the earlier one → past perfect (had done).
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.
Clause
- I missed the bus. — ✅ independent clause (stands alone)
- Because I overslept. — ❌ fragment (dependent clause, can't stand alone)
- Because I overslept, I missed the bus. — ✅ dependent + independent = complete sentence
- I missed the bus, and I was late. — ✅ two independent clauses joined by and
A clause is a unit built around a verb with a subject. Independent = can stand alone. Dependent = needs an independent clause to complete it.
Test: does the group of words have a subject + verb AND can it be a sentence on its own? Yes → independent clause. Has a subject + verb but feels incomplete → dependent clause.
B1 | Intermediate
- ✅ If I had more time, I would travel more. — second conditional
- ✅ The bridge was built in 1920. — passive voice
- ✅ She said she was tired. — reported speech with backshift
- ✅ Although it rained, we enjoyed the trip. — complex sentence with concession
These are B1 patterns — the CEFR intermediate level. At B1 you link ideas, use passive voice, handle reported speech, and manage second conditional — enough for travel, work basics, and everyday independence.
Marker: if you can explain why something happened and follow a news story, you're B1.
Medium
- If I were you, I would apologise. — one rule (second conditional), but distractors like was tempt you
- Answers require active thought, not instant pattern recognition
- Vocabulary and context are realistic, not artificially simplified
- Usually tests one rule, but the wrong answers are plausible
Medium marks middle-difficulty challenges: A2–B1, one rule tested, but with realistic distractors that require genuine understanding.
Use "Medium" when Easy feels too obvious but Hard feels overwhelming. This is where most productive learning happens — the sweet spot of difficulty.