The correct answers are:
- I apologize for dropping the bags of cash on my foot.
- I really don't mind spending a few months in a quiet jail cell.
- I look forward to meeting my new cellmate.
When a verb is followed by a preposition (like for in apologize for or to in look forward to), any following verb must be in the -ing form (gerund). The verb mind also takes a direct gerund object.
Admit to requires a gerund (admit to forgetting), and decide requires an infinitive (decided to confess).
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.
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.
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.
Infinitive
- ✅ I want to go. — to-infinitive after want
- ✅ She can swim. — bare infinitive after modal
- ✅ Let me help. — bare infinitive after let
- ❌ I enjoy to read. — wrong (enjoy takes gerund, not infinitive)
The infinitive has two forms: to-infinitive (to go) after verbs like want, decide, plan, hope; bare infinitive (go) after modals and causatives (let, make, help).
Rule: after want, need, decide, plan, hope, expect, agree, refuse → to-infinitive. After can, will, must, let, make → bare infinitive. After enjoy, avoid, finish → gerund, NOT infinitive.
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.
B2 | Upper Intermediate
- ✅ If I had studied harder, I would have passed. — third conditional
- ✅ The report is being reviewed by the committee. — passive progressive
- ✅ Having finished the exam, she left. — participle clause
- ✅ He denied having taken the money. — complex verb pattern
These are B2 patterns — the CEFR upper-intermediate level. At B2 you handle mixed conditionals, all passive forms, participle clauses, and can argue a point clearly. This is the level most universities and employers require.
Marker: if you can write a structured essay and debate an abstract topic, you're B2.
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.