Choose the phrase that best completes the dinner host's anxious thought.
I'm not entirely sure _____ lactose intolerant.
The correct answer is if the Martian is.
For indirect yes/no questions, we must use "if" or "whether" to connect the clauses, followed by standard Subject-Verb word order. "Is the Martian lactose intolerant?" becomes "...if the Martian is lactose intolerant."
Questions
- ✅ Do you like coffee? — do-support (no existing auxiliary)
- ✅ Can she swim? — inversion (auxiliary before subject)
- ✅ Where does he live? — wh-question
- ✅ You're coming, aren't you? — tag question
Questions require inversion (auxiliary before subject) or do-support (add do/does/did). Types: yes/no (Do you…?), wh- (What/Where/When…?), negative (Don't you…?), tag (…isn't it?).
Rule: find the auxiliary. Move it before the subject. No auxiliary? Add do/does/did. Never use just intonation in written English (You like coffee? is not standard).
Conjunction
- ✅ I was tired, but I stayed. — coordinating (links two equal clauses)
- ✅ I stayed because I was needed. — subordinating (introduces dependent clause)
- ✅ Although it rained, we went out. — subordinating (front position)
- ❌ I was tired, because. — incomplete (subordinating conjunction needs a clause after it)
Conjunctions connect words, phrases, or clauses. Coordinating (and, but, or, so, yet, for, nor) join equals; subordinating (because, although, if, when, while) introduce dependent clauses.
Pattern: coordinating = equal partners, same grammatical weight. Subordinating = one clause depends on the other for its meaning.
Be
- ✅ I am tired. / She is tired. / They are tired. — present
- ✅ I was tired. / They were tired. — past
- ✅ She is running. — auxiliary for progressive
- ✅ It was broken. — auxiliary for passive
Be has 8 forms (am/is/are/was/were/be/being/been) — the most irregular verb in English. Two jobs: copula linking subject to complement (She is a doctor) and auxiliary for progressive and passive.
Trap: be changes for person AND number in both present and past. No other English verb does this. Learn the grid: I am / you are / he is / we are + I was / you were / he was / we were.
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.