The correct answers are Each of the suspects has an alibi. and Every one of the suspects has an alibi.
When we want to use a plural noun ("suspects") after these quantifiers, we must use each of the or every one of the.
"Every of" does not exist in English. Furthermore, you cannot put "each" directly next to a plural noun without using "of the".
Determiner
- ✅ The cat sat on a mat. — articles as determiners
- ✅ My sister has three dogs. — possessive + numeral as determiners
- ❌ I went to the home. — wrong (idiomatic: I went home — no determiner)
- ❌ She is a good student. ✅ vs She is good student. ❌ — missing determiner
A determiner sits before a noun to specify which, how many, or whose. Types include articles, demonstratives, possessives, and quantifiers.
Rule: most singular countable nouns in English require a determiner — a cat, the cat, my cat, this cat. Dropping it (cat sat on mat) breaks the sentence.
Subject
- ✅ The list of items is wrong. — subject = list (singular), not items
- ❌ The list of items are wrong. — trapped by nearest noun
- ✅ Running is good exercise. — gerund as subject
- ✅ What he said surprised me. — clause as subject
The subject is the noun/pronoun/phrase before the verb that controls its number and person. Finding the true subject — especially through prepositional phrases — is the key to subject-verb agreement.
Rule: strip away prepositional phrases between subject and verb. Whatever's left is the true subject. The list (of items) is wrong.
Countable and uncountable
- ✅ some advice — ❌ an advice / advices (uncountable → no article, no plural)
- ✅ a piece of furniture — ❌ a furniture / furnitures
- ✅ How much water? — ❌ How many water? (uncountable → much)
- ✅ fewer people — ❌ less people (countable plural → fewer)
English nouns are either countable (take a/an, form plurals, use many/few) or uncountable (no plural, use much/little). The choice is partly arbitrary and must be memorised.
Test: can you put a number in front? Three chairs → countable. Three furnitures ❌ → uncountable. Use a unit phrase instead: three pieces of furniture.
A2 | Elementary | Pre-intermediate
- ✅ I went to the cinema yesterday. — past simple
- ✅ I have visited Paris twice. — present perfect (life experience)
- ✅ If it rains, I'll take an umbrella. — first conditional
- ✅ You should see a doctor. — modal for advice
These patterns are A2 — the second CEFR level. At A2 you move past survival phrases into real grammar: past tenses, the present perfect, basic conditionals, and modals for advice/obligation.
Marker: if you can describe yesterday and give simple advice, but struggle with abstractions or nuance, you're at A2.
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.