Key Concepts:
1. 'In' and 'into' are prepositions used to indicate location or movement.
2. 'In' is used to indicate being inside or within a place or object.
3. 'Into' is used to indicate movement or direction towards the inside of a place or object.

Usage Examples:
1. She is sitting in the car. (वह कार में बैठी है।)
2. The book is in the bag. (किताब बैग में है।)
3. He jumped into the pool. (उसने पूल में कूद दिया।)
4. The cat climbed into the tree. (बिल्ली ने पेड़ में चढ़ लिया।)

Key Mistakes:
1. Using 'in' instead of 'into' when indicating movement towards the inside of a place or object.
Incorrect: She jumped in the pool.
Correct: She jumped into the pool. (उसने पूल में कूद दिया।)

2. Using 'into' instead of 'in' when indicating being inside or within a place or object.
Incorrect: The book is into the bag.
Correct: The book is in the bag. (किताब बैग में है।)

Understanding the correct usage of 'in' and 'into' is essential for effective communication in English. By using these prepositions correctly, you can accurately convey your location or movement towards the inside of a place or object. Practice using 'in' and 'into' in different sentences to improve your English grammar skills.