Learn English grammar right from your phone with this app perfect for all non-native speakers. Thousands of questions with instant explanation, sorted by topic: - Nouns (plural, countable and uncountable, partitives/quantifiers...) - Articles (a, an, the, zero article) - Adjectives and adverbs (comparative and superlative. As or than? Good or well? Enough or enough of?) - Pronouns (Subject, reflex and possessive pronouns. There or it? Some or any? Or none?) - Tenses and verbs (Past, present and