Choose the correct order.
A phone was left on the bar. Someone came to pick it up.
Someone came to pick up the phone that was left on the bar.
Someone came to pick up the phone that was left on the bar.
That was left on the bar is the dependent clause saying something about the phone. The phone is it, so you use that to introduce it. The rest of the sentence uses normal word order.
Dependent clause
Dependent vs independent clause: an independent clause stands alone as a sentence (I was tired.). A dependent clause has a subject + verb but cannot stand alone (Because I was tired. ❌). The subordinating word is what makes it dependent — remove it and the clause becomes independent.
A dependent clause is introduced by a subordinating conjunction or relative pronoun and functions as an adverb, adjective, or noun inside a larger sentence.
Diagnostic: strip the opening word (because, if, who, which). Does the remainder work as a sentence? Yes → the original was dependent (the subordinator trapped it). No → deeper structural issue.
Independent clause
Independent vs dependent clause: both have subject + verb. The difference: independent clauses express a complete thought and stand alone. Dependent clauses start with a subordinator (because, if, who) and can't stand alone. Every sentence needs at least one independent clause.
An independent clause = subject + verb + complete thought. Sentence = one or more independent clauses (optionally with dependent clauses attached).
Diagnostic: can this group of words be a sentence on its own without feeling incomplete? Yes → independent clause. No → dependent or fragment.
Complex sentence
Complex vs compound sentence: a compound sentence links two equal independent clauses with and/but/or. A complex sentence links an independent clause with a subordinate (dependent) clause — one idea is the main point, the other is background.
A complex sentence = independent clause + dependent clause. The dependent clause adds time (when), reason (because), condition (if), or detail (who/which).
Diagnostic: are both halves able to stand alone? Yes → compound. Can only one stand alone? → complex.
B1 | Intermediate
B1 vs B2: B1 handles standard everyday communication and simple opinions. B2 handles abstract topics, sustained arguments, and nuanced register. If you can chat about your life but struggle to debate an issue or write a formal essay, you're B1.
B1 is the intermediate CEFR level: independent handling of familiar topics, second conditional, basic passive, reported speech, and linking words for cause and contrast.
Diagnostic: can you read a newspaper article on a familiar topic and summarise the argument? Comfortably → B2. Struggle with abstractions → still B1.
Hard
Hard vs Medium: Medium tests one rule with realistic distractors. Hard tests interacting rules, edge cases, or context-dependent answers where multiple options seem correct until you think deeply. If you're scoring 80%+ on Medium, try Hard to find your real gaps.
The Hard tag filters for B2+ challenges with layered difficulty: rule interactions, subtle distractors, and contexts that demand genuine grammatical reasoning.
Diagnostic: if Hard questions feel impossible, drop to Medium and master the individual rules first. Hard assumes you already know each rule — it tests whether you can apply them together.