"I do not keep their letter."
Translation:Saya tidak menyimpan surat mereka.
Why is it that for some exercises the prefix "men" is optional for verbs whereas my answer "Saya tidak simpan surat mereka" is marked wrong here? Is it because this is a "men" skill session?
Is it because this is a "men" skill session?
Yes, probably because it's a sentence from the "me-verbs".
In this sentence the base word is also a verb, so it should also work without the "me-" prefix.
But there are also "me-verbs" that have base words that are not verbs.
The purpose is to practice how the "me-" prefix can affect the base word.
For example :
simpan ==> menyimpan.
sapu ==> menyapu.
kirim ==> mengirim.