The correct answers are: By the time I reach 2050, the syndicate will have already stolen the artifact. At precisely midnight tomorrow, I might be interrogating the cyborg boss. The temporal portal is highly likely to close before I can jump back.
"Will have already stolen" correctly uses the future perfect to describe an action completed before a specific point in the future.
"Might be interrogating" pairs a modal of possibility with the continuous aspect to describe an action in progress at a future time.
"Is highly likely to" correctly expresses strong future probability.
"Will have been being" is incorrect because be is a stative verb and is rarely used in the continuous form for the future perfect (it should be will have been undercover).
"Must to be" is incorrect because true modals like must are followed by the bare infinitive (must be restored).
Future tense
If you've ever wondered why a native speaker said I'm meeting her tomorrow instead of I will meet her tomorrow — you've felt the future-tense puzzle. English has at least four common ways to talk about the future, and they're not interchangeable. Pick the wrong one and you sound either unnaturally formal or surprisingly vague about your own plans.
English uses several constructions for future time: will + infinitive (predictions, spontaneous decisions: I'll call), be going to (planned intentions, evidence-based predictions: It's going to rain), the present continuous for arrangements (I'm meeting Sam at six), and the present simple for fixed schedules (The train leaves at 8).
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.
Perfect tense
If you've ever written I am living here for ten years (should be have lived or have been living) — you've hit the perfect tense's main puzzle. English insists that "started in the past, still true now" lives in the present perfect, not the simple present. Get this clear and a whole class of common errors disappears.
The perfect aspect marks completion relative to a point in time, formed with have + past participle: I have eaten (present perfect), She had finished (past perfect), They will have arrived (future perfect). Combinable with progressive aspect (I have been working).
Progressive tense
If you've ever paused over I work in London vs I'm working in London and not been sure which to pick — you've hit the simple/progressive distinction. The first means it's your usual job; the second means it's temporary, going on right now. Native speakers reach for this distinction constantly without thinking; learners have to make it deliberate.
The progressive aspect marks ongoing action at a time of reference, formed with be + -ing: I am working, She was reading, They will be travelling. Marks temporary or in-progress events. Stative verbs (know, believe, own) don't normally take it.
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.