none. Do you say “all of them is” or “all of them are”? The answer is easy when you know the rules. In this grammar lesson, I explain subject-verb agreement, indefinite pronouns, and countable/uncountable nouns. This is especially important for business emails, academic essays, and IELTS/TOEFL/Cambridge exams. To follow up and master this subject, watch my lesson on countable and uncountable nouns and download my free resource, with lots of examples. No more subject-verb errors for you!