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Select the correct option:
This costs _________________________.

Noun goes immediately after the number, e.g., "five apples". We need the plural form of the noun - dollars.

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Grammatical number

Subject-verb agreement: the verb must match the subject's number, not the nearest noun. The list of items is long (✅) — not are, because the subject is list (singular), not items. This "attraction" error is the most common number mistake.

Grammatical number is the singular/plural system affecting nouns, pronouns, and verbs. Agreement means making them all match.

Diagnostic: find the actual subject (ignore prepositional phrases between subject and verb). Is it singular or plural? Match the verb to that.

Countable and uncountable

Countable vs uncountable: countable nouns can be numbered and pluralised (one book, two books). Uncountable nouns can't (information, not informations). The distinction determines your choice of article, quantifier (much/many, few/little), and whether the noun can be plural.

Countable = takes a/an, has a plural, uses many/few. Uncountable = no a/an, no plural, uses much/little. Some nouns are both depending on meaning (coffee = the substance vs a coffee = a cup).

Diagnostic: can you say one ___, two ___s? Yes → countable. No → uncountable (use a unit phrase: a piece of, a bit of).

A1 | Elementary | Beginners

A1 vs A2: A1 covers isolated survival phrases (Where is…?, I am…, How much?). A2 handles connected sentences about familiar routines and simple past events. If you can manage short fixed phrases but not string together original sentences about your day, you're still A1.

A1 is the entry level of the CEFR: greetings, introductions, numbers, basic present tense, and core function words.

Diagnostic: can you describe yesterday using past tense? No → A1. Yes → you're moving into A2.

Easy

Easy vs Medium vs Hard: Easy = one rule, obvious answer, A1A2. Medium = one rule but realistic distractors, A2B1. 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.