"Operasi penting untuk penyakit parah."

Translation: A surgery is important for a severe illness.

[GERG297672]

There is no need for 'A surgery' .. Surgery alone is correct
Lanawee is correct

[mapmanic]

In fact, if you really want to use an indefinite article, you could say: "An operation"... This would seem to be better for the translation, too. Actually, more common in American English than "surgery."

[lanawee]

Penting means important. A surgery is important for a severe illness.

Necessary means perlu. Necessary is not the same as important.

[donny309620]

"Operasi perlu untuk peyakit parah"

[aakaa81]

In that case it should be "diperlukan"

[XavierLamb9]

Shouldn't "adalah" be included in this sentence because without it sounds like it says "Important surgery"?

[Ms.Fixer]

You can't use "adalah" in this sentence because "adalah" can't bridge between a subject and an adjective. For more details, please review the tips for the Adjectives 1 skill.
If you want to say "Important surgery is for...", "Operasi yang penting untuk..." is grammatically correct.

[Bev425285]

A surgery for a severe illness is important should be accepted. Both translations, tho, are awkward.