will have known / will have been wearing
State verbs (like know, believe, own) cannot generally be used in continuous tenses. Even though there is a duration ("for exactly a year"), we must use the Future Perfect Simple (will have known), not the continuous form.
Action verbs (like wear, run, work) can be continuous. To emphasize how long an action will have been ongoing by a future point ("by the end of this month"), we use the Future Perfect Continuous (will have been wearing).
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.
Future tense
Will vs going to: the most confused future pair. Will = spontaneous decisions and predictions (I'll have the fish; It will rain). Going to = pre-existing plans and evidence-based predictions (I'm going to study law; Look at those clouds — it's going to rain). Swap them and you sound either impulsive or weirdly formal.
English encodes future time through will, be going to, present continuous (arrangements), and present simple (schedules) — each with different implications.
Diagnostic: is the decision happening right now? → will. Was it already planned? → going to. Is it a confirmed arrangement with another person? → present continuous.
Perfect tense
Present perfect vs simple past: I lost my keys (past: specific time, done). I have lost my keys (perfect: result matters NOW — I still don't have them). The perfect always connects past action to present relevance. If the time is specified (yesterday, in 2010) → simple past. If the result matters now → present perfect.
The perfect aspect = have + past participle. Marks completion relative to a time point. Three forms: present/past/future perfect.
Diagnostic: does the sentence mention a specific finished time (yesterday, last year, in 1999)? → simple past. Is it about the result/relevance NOW? → present perfect.
Progressive tense
Progressive vs simple: I work in London (permanent job) vs I am working in London (temporary assignment). Simple = fact/habit/permanent. Progressive = ongoing/temporary/in-progress. Same verb, different aspect, different meaning. The choice isn't about grammar preference — it changes what you're communicating.
The progressive = be + -ing. Marks ongoing/temporary actions. Stative verbs resist it.
Diagnostic: is the action happening RIGHT NOW and likely to stop? → progressive. Is it a general truth, habit, or scheduled event? → simple. Is the verb stative (know, own, believe)? → simple (even if happening now).
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.
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.