1. My book is more expensive than this book.
2. Who does this house belong to?
3. They enjoy walking in the rain.
4. Nam has been learning English for five years.

1 This book is cheaper than my book.
=>My book is more expensive than this book.
2 Who owns this house ?
=>Who does this house belong to?
3 They like to walk in the rain.
=>They enjoy walking in the rain.
4 Nam began learning english five years ago
=>Nam has been learning English for five years