Complete the alien commander's report on Earth's internet.
"The internet has a strange ___ on humans; ___ constantly distracting them from building spaceships."
The correct answer is effect / it's.
You need the noun effect because you are talking about the result of the internet (a strange effect).
You need the contraction it's because the sentence requires "it is" to make sense (it is constantly distracting them).
Noun
A noun is a word that names something — a person, place, thing, idea, action, or quality. Nouns are one of the open word classes in English, alongside verbs, adjectives, and adverbs. They typically appear as the subject or object of a clause, after articles or adjectives, and as the head of a noun phrase.
Recognising nouns reliably is the foundation for nearly every other grammar topic — agreement, articles, plurals, possessives, and prepositions all depend on it. Get this right and the rest of English grammar starts to fall into place.
Verb
A verb is a word that expresses an action, a state, or an occurrence — the engine of every English sentence. Most verbs have five forms: base (go), -s form (goes), past tense (went), past participle (gone), and -ing form (going). The verb be is the major exception with eight forms; modal verbs like can and must have fewer.
Verbs carry tense (when), aspect (how it unfolds), mood (the speaker's attitude), and voice (active vs passive). Mastering them is foundational — virtually every other grammar topic depends on getting verbs right.
Pronoun
A pronoun is a small, closed class of words that stands in for a noun or noun phrase. The main types: personal (I, you, he, she, it, we, they) plus their object (me, him) and possessive (my, mine) forms; demonstrative (this, that); relative (who, which, that); interrogative (who, what); and reflexive (myself, yourself).
Pronouns are how English avoids endlessly repeating names. The catch: their meaning depends entirely on context, so unclear pronoun reference (Tom told Mike that he was wrong — who's he?) is one of the most common writing problems.
Apostrophe
The apostrophe ( ' ) is a punctuation mark with two main jobs in English: marking missing letters in contractions (do not → don't, they are → they're) and showing possession with nouns (the eagle's feathers, one month's time). It's not used for plurals — cats never takes an apostrophe, even though many writers slip and add one.
Mixing up its (possessive) and it's (contraction of it is), or writing banana's £1 on a market sign, are the giveaway errors that mark a writer as careless. Getting the apostrophe right is one of the highest-leverage punctuation skills you can learn.
Possessive
The possessive form shows ownership or association in English. With most nouns, you add 's (Sarah's book, the dog's tail); with plural nouns ending in s, you add just an apostrophe (the students' essays). Pronouns have irregular possessives — both possessive determiners (my, your, his, her, our, their) and possessive pronouns (mine, yours, his, hers, ours, theirs).
The most-mixed-up pair: its (possessive of it) vs it's (= it is). Possessive its takes no apostrophe; it's always means it is or it has. Getting this right is one of the highest-leverage punctuation moves in English.
B2 | Upper Intermediate
B2 is the upper-intermediate level in the CEFR framework, sitting between B1 and C1. At B2 you can read editorials, follow most TED talks without subtitles, and hold extended conversations on abstract topics — including topics outside your everyday life.
Grammatically, B2 means flexible control of mixed conditionals, passive voice across tenses, reported speech with proper backshifting, and participle clauses. B2 is the standard target for university entrance exams (IELTS 5.5–6.5, TOEFL 87–109) and most skilled-migration thresholds — knowing whether you're there shapes your study plan.
Difficulty: Medium
The Medium difficulty tag marks questions and challenges in the middle of the difficulty range — typically suitable for A2 to B1 learners. Expect a single rule with realistic distractors, longer sentences, and contexts where you have to think before answering rather than reading off the obvious choice.
Filter by Medium when you're past the absolute basics and ready to consolidate. It's the level where most lasting progress happens — easy enough that you can finish without exhausting concentration, hard enough that getting it right means you've actually understood.