The correct answers are Ought we to rattle the chains before or after midnight? and You ought not to wail so loudly when the master is sleeping.
Ought is unique because it acts like a modal auxiliary (it inverts for questions and takes "not" directly for negations) but it almost always requires a to-infinitive*.
Question form: Ought + subject + to + verb (Ought we to rattle...?)
Negative form: Ought + not + to + verb (You ought not to wail...)
"Didn't ought" and "Do we ought" are incorrect because "ought" does not take do-support in standard English. "We ought rattle" is incorrect because it is missing the mandatory "to".
Modal verb
If you've ever struggled with the difference between You must do this (strong command) and You should do this (advice) — or It might rain (possible) and It will rain (certain) — you've felt how much modal verbs do in English. They're how the language signals certainty, obligation, possibility, and politeness, and getting them right is what stops your speech from sounding either pushy or wishy-washy.
A modal verb is an auxiliary — can, could, may, might, must, shall, should, will, would — adding meaning around ability, permission, possibility, obligation, or speculation. Always followed by the bare infinitive (can swim, never can to swim), and never inflected for person.
Auxiliary verb
If you've ever wondered why English asks Do you know? instead of Know you?, or how a single sentence can carry tense, aspect, AND voice (has been being cleaned), you've felt the work of auxiliary verbs. They're tiny words that quietly carry most of English's grammatical machinery — get them wrong and questions, negatives, and tenses all fall apart.
An auxiliary verb combines with a main verb to add grammatical meaning. The English auxiliaries are be, have, do, and the modal verbs (can, will, should…). They handle questions (Do you?), negation (don't), tense and aspect (has gone, is going), and passive voice (was eaten).
Negation
If your native language uses double negatives (I don't see nothing) — like Russian, Spanish, or French — you've probably been told this is wrong in English and not been entirely sure what the fix is. Standard English uses one negative per clause: either I saw nothing or I didn't see anything, never both. Once you internalise that single rule, your written English clears up a lot.
Negation in English uses not after an auxiliary or modal verb: I am not going. Without an auxiliary, you add do-support (I do not go). Negative words like never and nobody already negate the clause — adding not on top creates non-standard double negatives.
Questions
If you've ever asked You like coffee? with rising intonation and gotten a confused look — you've felt the gap between casual and grammatical English questions. Many languages form questions with intonation alone, but English usually requires inversion (Are you ready?) or do-support (Do you like coffee?). Skip the structure and your questions sound like uncertain statements.
Questions in English use inversion of subject and an auxiliary (Can she dance?) or do-support when no auxiliary is present (Does the milk go in the fridge?). Yes/no questions, wh-questions, negative questions, and tag questions all share this machinery.
Infinitive
If you've ever written I enjoy to swim or He let me to go and only later learned why both are wrong — you've hit the infinitive's main puzzle. English is fussy: some verbs demand the to-infinitive, some demand the bare infinitive, some demand the gerund, and a few accept multiple options with different meanings (remember to lock vs remember locking).
The infinitive is the basic form of a verb, used non-finitely. The to-infinitive (to go) follows verbs like want, decide, plan; the bare infinitive (go) follows modal verbs (can, will) and causatives (Let him go).
C1 | Advanced
If you've ever sat through a lecture in English, written a complaint letter, or argued a point in a meeting and come out feeling actually understood — not just tolerated — you've felt what C1 looks like. The level matters because it's where most universities, certifications, and skilled-work environments draw their language line.
C1 is the advanced level in the CEFR framework, demanding fluent and flexible language: inversion for emphasis, mixed and advanced conditionals, formal subjunctive, cleft sentences, and complex nominal phrases — all used appropriately across registers.
Difficulty: Hard
If easy and medium questions are clicking but you still feel exposed in real conversation or formal writing, you've outgrown the basics. Hard material is where the gaps you didn't know you had show up: the distractor that "sounds right", the rule that interacts with another rule, the case where context changes the answer. It's where genuine fluency is built.
The Hard difficulty tag marks upper-intermediate to advanced challenges — typically B2 and above. Interacting rules, edge cases, plausible distractors, and contexts that require genuine understanding rather than surface pattern-matching.