"Guard this book well."

Translation: Jagalah buku ini dengan baik.

[BarefootB]

it looks quite strange: 'dengan baik'... why not simply baik? It's been used that way in many other sentences

[Hans_Se]

I think because "well" is an adverb (adverb of manner to be precise)

another example
1. Clearly : dengan jelas
2. Carefully : dengan hati-hati
3. Quickly : dengan cepat
4. Slowly : dengan lambat

[DuskyDaniel]

I believe if the adjective describes a verb, you'll have to use 'dengan'

[Bij42379]

Whats the difference between "baik" and "bagus" other than "context"? Can some one explain the different contexts please?

[Graeme984993]

Why can't jaga be used?

[Nick.Kly]

+1: what's the difference between 'jaga' and 'jagalah'?

[Maximalkan]

Looks like jagalah is the imperative form of jaga, used for questions or commands. Here -lah is added at the end of jaga.

[MarkusGrantus]

“Jagalah” is a command/demand compared to “mohon jaga” where someone is politely requesting.

[jadezahrap]

Another translation could be... look after my book well instead of guard

[vemmv]

Yes, guard implies that it's a very important book. Look after is more appropriate when it's just an ordinary book.

[Kai660177]

menjaga buku ini dengan baik?