ArticlesThe full system, including the zero article in abstractions.Related learning areasEnglish GrammarRelated conceptsAdjectives as nouns, and adjective orderAuxiliary verbs in echoes, agreement, and emphasisClauses of contrast and purposeFuture perfect and future continuousGerunds and infinitivesNarrative tenses, including past perfect continuousQuestionsAll questions in this subjectStart learningStart free practice