Grammar rules and exercises are indeed mentioned in the NCERT English textbook for Class 4. These rules and exercises are designed to help students understand and practice various aspects of English grammar. Let's explore them in detail:

1. Noun, Pronoun, and Verb:
- The textbook introduces and explains nouns, pronouns, and verbs.
- It provides examples and exercises to help students identify and use these parts of speech correctly.

2. Tenses:
- The textbook covers different tenses, such as present, past, and future.
- It explains how to form sentences using different tenses and provides exercises to reinforce learning.

3. Subject-Verb Agreement:
- The concept of subject-verb agreement is discussed, emphasizing the importance of using the correct verb form based on the subject.
- The textbook presents examples and exercises to help students grasp this rule.

4. Articles:
- The use of articles (a, an, the) is explained in the textbook.
- The rules for when to use indefinite articles (a, an) and definite article (the) are illustrated through examples.

5. Adjectives and Adverbs:
- Adjectives (words that describe nouns) and adverbs (words that describe verbs) are introduced.
- The textbook provides exercises to practice using adjectives and adverbs correctly.

6. Prepositions:
- The concept of prepositions (words that show relationships between other words) is covered.
- Students learn how to use prepositions in sentences through examples and exercises.

7. Sentence Construction:
- The textbook guides students on how to construct grammatically correct sentences.
- It explains the role of subject and predicate in a sentence and provides exercises for practice.

Overall, the NCERT English textbook for Class 4 offers a comprehensive introduction to grammar rules and provides exercises to reinforce learning. By following these rules and practicing the exercises, students can enhance their understanding and application of English grammar.