The correct answers are Walking to the bus stop, I got caught in the pouring rain and As I was walking to the bus stop, the rain started pouring.
Error: dangling participle — the subject of "Walking" must match the subject of the main clause. The rain wasn't walking! Fix it by making a person the subject, or rewrite with a full clause ("As I was walking…").
Participle
Present participle vs gerund: both are -ing forms, but a participle acts as an adjective/adverb (the running water, She sat reading), while a gerund acts as a noun (Running is fun). Same form, different grammatical job.
A participle = verb form used as modifier or in compound tenses. Present (-ing): progressive + adjective. Past (-ed/irregular): perfect + passive + adjective.
Diagnostic: is the -ing word describing a noun or modifying a verb? → participle. Is it being a noun (subject, object)? → gerund.
Clause
Clause vs phrase: a clause has a subject + verb (she runs); a phrase does not (in the morning, running fast). This is the first distinction to make when analysing sentence structure.
A clause is a grammatical unit built around a verb: independent clauses make complete sentences; dependent clauses attach to them as modifiers or complements.
Diagnostic: find the verb. If there's a subject doing or being something → clause. If there's no subject-verb pair → phrase.
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.
Medium
Medium vs Easy: Easy has one obviously correct answer and clearly wrong distractors. Medium has one correct answer but plausible distractors — you need to actually know the rule, not just guess from sound.
The Medium tag filters for A2–B1 challenges with realistic difficulty: one rule per question, plausible alternatives, everyday contexts.
Diagnostic: if you're scoring 90%+ on Easy, move here. If you're below 60% on Medium, go back to Easy for that topic. Target 70–80% accuracy for maximum learning.