Choose the correct word to complete the eccentric billionaire's last will and testament.
"I stipulate that my beloved pet penguin, Sir Waddles, _____ fed only the finest imported caviar every morning."
The correct answer is be.
Formal verbs of commanding or stipulating (like "stipulate", "demand", or "order") require the base form of the verb in the that-clause. For the verb "to be", the base form is simply "be", even for third-person singular subjects like "Sir Waddles".
Subjunctive mood
- ✅ If I were you… — past subjunctive (not was)
- ✅ I suggest that he go. — present subjunctive (not goes)
- ✅ It's important that she be present. — present subjunctive
- ❌ If I was you… — common in speech, avoided in formal writing
The subjunctive uses bare-infinitive forms (go, be) after verbs of demand/suggestion, and were (not was) in unreal/hypothetical conditions. Two contexts: that-clauses (I insist that he leave) and if-clauses (If she were here).
Rule: after suggest/recommend/demand/insist that… → use base form. In if + unreal condition → use were for all persons.
Verb mood
- Indicative: She goes every day. — stating fact
- Imperative: Go now. — giving command
- Subjunctive: I suggest she go. — hypothetical/recommendation
- Conditional: She would go if asked. — dependent on condition
Verb mood marks the speaker's attitude: indicative (fact), imperative (command), subjunctive (unreal/recommended), conditional (would/could). English barely marks mood morphologically — mostly through auxiliaries and word order.
Rule: stating a fact? → indicative. Giving a command? → imperative. Imagining/recommending? → subjunctive or conditional. The mood determines which verb forms and auxiliaries you use.
Clause
- I missed the bus. — ✅ independent clause (stands alone)
- Because I overslept. — ❌ fragment (dependent clause, can't stand alone)
- Because I overslept, I missed the bus. — ✅ dependent + independent = complete sentence
- I missed the bus, and I was late. — ✅ two independent clauses joined by and
A clause is a unit built around a verb with a subject. Independent = can stand alone. Dependent = needs an independent clause to complete it.
Test: does the group of words have a subject + verb AND can it be a sentence on its own? Yes → independent clause. Has a subject + verb but feels incomplete → dependent clause.
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.
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.