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Complete a student's highly dramatic email explaining to their professor why they missed the morning lecture.
I am so sorry I missed class! I _________________________ my bicycle to campus when a brave squirrel suddenly _________________________ into my basket. It _________________________ my essay and immediately ran up a tree!

Answers and Explanations:

  • I was riding my bicycle...

    The past progressive describes the ongoing background action (the bicycle ride) that gets interrupted.

  • ...when a brave squirrel suddenly jumped...

    The past simple is used for the sudden, interrupting event.

  • It grabbed my essay and immediately ran...

    We use the past simple for a sequence of completed actions in a story ("grabbed" happened first, then it "ran"). Using the progressive here would sound like the squirrel was grabbing the essay in slow motion while running!

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Verb

  • walk → walk / walks / walked / walked / walking (5 forms, regular)
  • go → go / goes / went / gone / going (5 forms, irregular)
  • be → am/is/are/was/were/be/being/been (8 forms)
  • can → can / could (modal: only 2 forms, no -s, no -ing)

A verb is the one word class every English sentence requires. Carries tense (when), aspect (duration), mood (attitude), and voice (active/passive). Regular verbs add -ed; ~200 irregular verbs have unpredictable past forms.

Key insight: fix your verbs and most grammar problems disappear. Wrong tense, wrong agreement, wrong form — verb errors account for the majority of grammatical mistakes.

Past tense

  • I walked home. — simple past (completed action)
  • I was walking when it rained. — past progressive (in progress)
  • I had already left when she arrived. — past perfect (earlier past)
  • I had been waiting for an hour. — past perfect progressive (duration up to a past point)

Four past tense forms: simple past (done), past progressive (was happening), past perfect (had already happened), past perfect progressive (had been happening). Each encodes different timing relative to other past events.

Pattern: simple past = the story's main timeline. Past progressive = background action. Past perfect = flashback to something even earlier.

Simple tense

  • I go to work every day. — present simple (habit)
  • She went home yesterday. — past simple (completed action)
  • I will call you later. — future simple (promise/decision)
  • Water boils at 100°C. — present simple (general truth)

The simple aspect is the default, unmarked verb form. Present simple = habits, facts, schedules. Past simple = completed actions. Future simple = predictions, promises, decisions. No auxiliary needed (except will for future and do for questions/negatives).

Rule: if the action is a fact, habit, completed event, or scheduled future — and you don't need to emphasise it being in-progress or connected to now → simple tense.

Progressive tense

  • I am working in London. — temporary, happening now
  • I work in London. — permanent/habitual (simple)
  • I am knowing the answer. — stative verb, can't be progressive
  • She was reading when I arrived. — past progressive (in progress at that moment)

The progressive = be + -ing. Marks actions as ongoing, temporary, or in-progress at a reference time. NOT used with stative verbs (know, believe, own, want, like) unless meaning shifts.

Rule: is the action temporary/in-progress right now? → progressive. Is it a permanent fact, habit, or schedule? → simple. Is it a stative verb? → almost never progressive.

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: A2B1, 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.