The present simple verb form are indicates we need to use the present continuous form of the main verb get: They are getting. In the affirmative form we must use used to, not use to.
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).
Be
- ✅ I am tired. / She is tired. / They are tired. — present
- ✅ I was tired. / They were tired. — past
- ✅ She is running. — auxiliary for progressive
- ✅ It was broken. — auxiliary for passive
Be has 8 forms (am/is/are/was/were/be/being/been) — the most irregular verb in English. Two jobs: copula linking subject to complement (She is a doctor) and auxiliary for progressive and passive.
Trap: be changes for person AND number in both present and past. No other English verb does this. Learn the grid: I am / you are / he is / we are + I was / you were / he was / we were.
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.
Habitual aspect
- ✅ I walk to work every day. — present simple (current habit)
- ✅ I used to smoke. — past habit, no longer true
- ✅ Every summer we would go to the lake. — repeated past action
- ❌ I would live in Paris. — wrong (would for habitual needs an action, not a state)
The habitual aspect marks actions as repeated/routine: present simple (now), used to (past, stopped), would (past repeated actions within a time frame).
Rule: used to works for both states and actions. Would works only for repeated actions — never states (I used to know him ✅, not I would know him ❌).
C1 | Advanced
- ✅ Not only did she finish early, but she also helped others. — inversion for emphasis
- ✅ It is the process that matters, not the result. — cleft sentence
- ✅ I insist that he be present. — formal subjunctive
- ✅ Were I to disagree, I would say so. — inverted conditional
These are C1 structures — the CEFR advanced level. At C1 you control inversion, cleft sentences, subjunctive forms, and register-switching fluently across formal and informal contexts.
Marker: if you can restructure a sentence for rhetorical effect without hesitation, you're C1.
Hard
- Had she not intervened, the situation would have escalated. — inverted conditional
- All distractors are grammatically plausible in other contexts
- Multiple rules interact (e.g., tense + aspect + modality)
- Context determines the answer — no single "rule" is enough
Hard marks upper-intermediate to advanced challenges: B2+, interacting rules, edge cases, plausible distractors, and contexts where pattern-matching fails.
Use "Hard" when Easy/Medium feel trivial and you want to test whether you actually understand a rule versus just recognising surface patterns.