Mayor Higgins, who was last seen eating a giant donut, is our prime suspect. We need to find the specific donut shop that sells these rare rainbow sprinkles. The Golden Crumb Bakery, which is located on Main Street, was robbed at midnight.
When to use commas:
- When a person or place is uniquely identified by their proper name (Mayor Higgins, The Golden Crumb Bakery), any descriptive clause that follows is just extra information. This is a non-defining clause. It needs commas, and you must use "who" for people or "which" for things (never "that").
- When the noun is general and needs identification ("the specific donut shop"), the clause is defining. It provides essential information, so we use no commas and can use "that".
Relative clause
- ✅ The man who called is my uncle. — restrictive (essential: which man?)
- ✅ My uncle, who lives in Paris, called. — non-restrictive (extra info, commas)
- ❌ My uncle that lives in Paris — wrong (that can't introduce non-restrictive)
- ✅ The book that I read = The book I read — restrictive (pronoun optional)
Relative clauses modify nouns using who/whom/whose/which/that or where/when/why. Restrictive = essential, no commas, that OK. Non-restrictive = extra, needs commas, uses which/who (never that).
Rule: if you can remove the clause and still know which noun is meant → non-restrictive (commas). If removing it makes the noun ambiguous → restrictive (no commas).
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.
Punctuation
- Period (.) — ends statements
- Comma (,) — separates within sentences
- Semicolon (;) — links related independent clauses
- Colon (:) — introduces what follows
- Question mark (?) — ends direct questions
- Apostrophe (') — possession + contractions
Punctuation marks signal sentence structure to the reader: where thoughts end, how they connect, what's quoted, and what belongs to whom. ~12 marks, each with specific rules.
Key insight: punctuation isn't about pauses in speech. It's about grammatical structure. Learn the structure, and the punctuation follows.
Comma
- ✅ apples, pears, and figs — list separator
- ✅ My brother, a doctor, called. — non-essential info set off by commas
- ✅ I went home, and she stayed. — comma before conjunction joining two clauses
- ❌ I went home and she stayed. — missing comma (two independent clauses need one before and)
The comma ( , ) separates elements within a sentence: list items, non-essential phrases, introductory words, and clauses joined by coordinating conjunctions.
Rule: if two independent clauses are joined by and/but/or, put a comma before the conjunction. If it's just a compound verb (same subject), no comma.
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.