Which of the following sentences expresses that it is not true that John is at home?
Answers:
"Must not" is used to express a strong belief that something is not true. The correct sentence is "John must not be at home."
Auxiliary verb
- ✅ Do you know? — ❌ Know you? (English requires do-support for questions)
- ✅ She has finished. — ❌ She finished has. (auxiliary before main verb)
- ✅ They are leaving. — ❌ They leaving. (progressive needs be)
- ✅ He doesn't smoke. — ❌ He smokes not. (negation needs do)
Auxiliary verbs (be, have, do, and the modals) combine with main verbs to build questions, negatives, tenses, aspects, and passive voice.
Pattern: if you need to ask a question, negate, or stack tense/aspect — you need an auxiliary. The main verb carries meaning; the auxiliary carries grammar.
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.
Modal verb
- ✅ She can swim. — ❌ She can to swim. (modal + bare infinitive, no to)
- ✅ You must leave now. — strong obligation
- ✅ It might rain. — possibility (~50%)
- ✅ He should apologise. — advice/recommendation
Modal verbs (can, could, may, might, must, shall, should, will, would) are auxiliaries expressing ability, permission, possibility, obligation, or speculation. Always + bare infinitive. Never inflected (she can, not she cans).
Rule: modals never take to after them, never add -s for third person, and can't combine directly (must can ❌ — use must be able to).
Negation
- ✅ I don't see anything. — ❌ I don't see nothing. (double negative in standard English)
- ✅ She never goes out. — never already negates (no doesn't needed)
- ✅ He doesn't like coffee. — do-support for negation
- ✅ Nobody came. — negative subject (no auxiliary needed)
Negation uses not after an auxiliary/modal, or do-support when there's no auxiliary. One negative per clause in standard English — never, nobody, nothing already negate without adding not.
Rule: one negative element per clause. I don't see anything or I see nothing — never both together in standard English.
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.
Easy
- She is a teacher. — one verb form, one rule
- I have two cats. — basic possession, short sentence
- He doesn't like coffee. — simple negation with do-support
- Only one answer is clearly correct; distractors are obviously wrong.
Easy marks beginner-level challenges: A1–early A2, one rule at a time, everyday vocabulary, no trick questions.
Use "Easy" when you want to build confidence on a specific rule without interference from other grammar or tricky contexts.