แปลว่า:She likes giving her sister a book.
This is not natural sounding English because the simple present tense is used for making general statements while the indefinite article is used for the opposite. The most natural way to say this would be:
- She likes giving her sister books
With singular "a book" it makes it sound like she habitually gives the same book to her sister over and over. "A book" works in different contexts:
- She is giving her sister a book
- She will give her sister a book
- She gave her sister a book
- She wants to give her sister a book