I succeeded in getting past the evil villain's laser grid. Instead of using the front door...
Preposition + -ing: The verb succeed is always followed by the preposition in. Furthermore, whenever a verb directly follows a preposition (like in or of), it must be in the gerund form (-ing).
Preposition
- ✅ interested in — ❌ interested on
- ✅ good at football — ❌ good in football
- ✅ depend on — ❌ depend of
- ✅ arrive at the station — ❌ arrive to the station
Prepositions link nouns to the rest of the sentence: time (at 5pm), place (in London), manner (with care), abstract (afraid of). Most are idiomatic — the "correct" preposition must be memorised with each verb/adjective combination.
Rule: there is no universal rule. English prepositions are learned by combination: interested IN, good AT, depend ON, afraid OF. Your native language's equivalent will often mislead.
Gerund
- ✅ I enjoy reading. — ❌ I enjoy to read.
- ✅ She's good at swimming. — ❌ She's good at to swim.
- ✅ He avoids making eye contact. — gerund after avoid
- ✅ Running is good exercise. — gerund as subject
A gerund is the -ing form of a verb functioning as a noun. It follows verbs like enjoy, avoid, finish, mind and ALL prepositions. Never use an infinitive where a gerund is required.
Rule: after a preposition (at, in, of, about, without) → always gerund. After enjoy, avoid, finish, mind, suggest, deny → always gerund.
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.
Collocations
- ✅ make a decision — ❌ do a decision
- ✅ strong coffee — ❌ powerful coffee
- ✅ heavy rain — ❌ strong rain
- ✅ highly unlikely — ❌ very unlikely (grammatical, but less natural)
Collocations are word pairs that English habitually puts together. Both options may be grammatically valid, but one sounds native and the other doesn't.
Pattern: there's no logic to predict them — you make decisions but do homework, you have strong coffee but heavy rain. They must be learned as chunks, not deduced from rules.
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: A2–B1, 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.