The correct answers are My mood swings from happy to sad without warning, I go through phases of feeling really optimistic, Sometimes I'm in a funk for days, and My spirits lift when I spend time in nature.
Moods "swing" between states, we "go through phases" of different feelings, being "in a funk" means feeling depressed, and spirits "lift" when we feel better. We don't "make changes" with emotions or "do mood shifts" - emotions "change" or we "experience mood shifts."
Verb
Verb vs noun vs adjective: nouns name things. Adjectives describe. Verbs express what happens or what IS. The test: can it take tense (walked, will walk)? Can it take -ing? Can it follow to as an infinitive (to walk)? Yes to any → verb. English often converts freely between classes (run = noun or verb), so context decides.
A verb = action/state/occurrence word. 5 forms (base, -s, past, past participle, -ing). Carries tense, aspect, mood, voice. The one required element in every sentence.
Diagnostic: does it change for tense (walk → walked)? Can you put to before it (to walk)? Does it take -ing (walking)? → verb.
Phrasal verb
Phrasal verb vs verb + preposition: a phrasal verb has a non-literal combined meaning (run into = meet by chance). A verb + preposition keeps its literal meaning (run into the room = physically run inside). The test: is the meaning predictable from the parts? No → phrasal verb. Yes → just a verb followed by a preposition.
Phrasal verbs combine verbs with particles/prepositions to create new meanings. They're the single biggest gap between textbook English and real native usage.
Diagnostic: can you guess the meaning from the individual words? No → phrasal verb (learn as unit). Yes → literal verb + preposition.
Collocations
Collocation vs idiom: both are fixed expressions, but collocations are transparent (you can guess the meaning from the words: heavy rain = a lot of rain), while idioms are opaque (kick the bucket ≠ literally kick anything). Collocations are about which words pair naturally; idioms are about hidden meaning.
Collocations are habitual word combinations: make a decision, strong coffee, take a shower. Grammar allows alternatives, but fluency demands the conventional pairing.
Diagnostic: if the meaning is clear but the combination sounds "off" to native ears (do a mistake instead of make a mistake) — it's a collocation issue.
Vocabulary for B2/Upper Intermediate
B2 vs C1 vocabulary: B2 gives you precision within common topics. C1 adds low-frequency academic/professional vocabulary and full register sensitivity — knowing that commence is formal, start neutral, kick off informal, and choosing appropriately. The jump is from "precise" to "stylistically aware."
B2 vocabulary = ~4,000–6,000 words. Hedging, reporting verbs, idioms, figurative language, register-appropriate synonyms.
Diagnostic: can you write a formal essay with appropriate hedging and varied vocabulary? Yes → B2. Does your formal writing still sound slightly informal or your informal writing oddly stiff? → need C1 register control.
B2 | Upper Intermediate
B2 vs C1: B2 means effective communication on complex topics with some effort. C1 means effortless fluency with precise register control. If you can argue a point but still reach for words and make structural slips under pressure, you're B2.
B2 is the upper-intermediate CEFR level: mixed conditionals, complex passives, reported speech with backshift, participle clauses, and sustained written argument.
Diagnostic: does your writing read as "competent non-native" or "could be native"? The former → B2. The latter → C1.
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.