The correct answers are Humans usually sleep at night, but my human roommate is studying right now. and I am living in a university dorm this semester, but humans generally live in houses.
Explanation:
- usually sleep / is studying: Present Simple is used for routines ("usually sleep"), while Present Continuous is for actions happening right now ("is studying").
- am living / generally live: Present Continuous is perfect for temporary situations ("this semester"), while Present Simple is for permanent facts or general truths ("generally live").
- is boiling is incorrect because scientific facts and general truths require the Present Simple ("boils").
- learn... this week is incorrect because a temporary, ongoing action around the present time requires the Present Continuous ("am learning").
Present tense
Simple present vs present progressive: simple present = habits, routines, permanent facts (I work here). Present progressive = right now, temporary, changing (I'm working from home today). The most common confusion: using progressive for habits (I'm working here ❌ for permanent job) or simple for right-now (I work now ❌ for current activity).
The present tense has four forms: simple, progressive, perfect, perfect progressive — each relating the action to "now" differently.
Diagnostic: is it a habit/permanent fact? → simple. Happening right now? → progressive. Started in past but still relevant? → perfect. Ongoing duration up to now? → perfect progressive.
Simple tense
Simple vs progressive vs perfect: simple = "just the fact" (I work). Progressive = "ongoing right now" (I am working). Perfect = "connected to a reference time" (I have worked). Simple is the default — use it unless you have a reason to add progressive or perfect meaning.
The simple aspect = unmarked form. Habits, facts, completed events, scheduled future. The starting point for all tense learning.
Diagnostic: do you need to signal "ongoing" (progressive) or "relevant to now" (perfect)? No? → simple is correct. Most sentences use simple tense — it's the unmarked default.
Progressive tense
Progressive vs simple: I work in London (permanent job) vs I am working in London (temporary assignment). Simple = fact/habit/permanent. Progressive = ongoing/temporary/in-progress. Same verb, different aspect, different meaning. The choice isn't about grammar preference — it changes what you're communicating.
The progressive = be + -ing. Marks ongoing/temporary actions. Stative verbs resist it.
Diagnostic: is the action happening RIGHT NOW and likely to stop? → progressive. Is it a general truth, habit, or scheduled event? → simple. Is the verb stative (know, own, believe)? → simple (even if happening now).
Humor
Humor vs serious practice: both teach the same rules. The difference is engagement — funny material keeps you coming back and creates stronger memory hooks. If dry drills bore you into quitting, humorous practice is more effective because you actually do it.
The Humor tag filters for entertaining practice: silly contexts, wordplay, absurd examples — all testing real grammar rules underneath.
Diagnostic: if you find yourself dreading practice → try filtering by Humor. If you're preparing for a formal exam and want serious register → filter it out.
B1 | Intermediate
B1 vs B2: B1 handles standard everyday communication and simple opinions. B2 handles abstract topics, sustained arguments, and nuanced register. If you can chat about your life but struggle to debate an issue or write a formal essay, you're B1.
B1 is the intermediate CEFR level: independent handling of familiar topics, second conditional, basic passive, reported speech, and linking words for cause and contrast.
Diagnostic: can you read a newspaper article on a familiar topic and summarise the argument? Comfortably → B2. Struggle with abstractions → still B1.
Easy
Easy vs Medium vs Hard: Easy = one rule, obvious answer, A1–A2. Medium = one rule but realistic distractors, A2–B1. Hard = interacting rules, edge cases, B2+. Start Easy to check you have the basics before moving up.
The Easy tag filters for single-rule, short-sentence, common-vocabulary challenges designed for beginners or for anyone wanting a confidence check on fundamentals.
Diagnostic: if you get Easy questions wrong, stay here — your foundations need work. If they feel trivial, move to Medium.