"I will try writing letters this Saturday."
Translation:Tôi sẽ thử viết thư vào thứ bảy này.
In fact, there is a slight difference though "thử" and "cố gắng" can be used in this case.
In this course, if there is a classifier and plural indicator you would translate as 'the letters', which suggests a specific set of letters. If you see the noun on its own, without a classifier then it's normally plural and has no article 'the'.
But then you have to contrast that versus a sentence from this same module:
Cô ấy viết thư cảm ơn cho chúng tôi
So, as you say, I put down
"She writes thank you letters to (for) us"
No 'một', no tờ, right? Generic plural, right?
But that's marked wrong, instead it says "A thank you letter".
So there's an unexplained inconsistency.
Yes this is the kind of inconsistency in dl that makes me soo surprised and sometimes mad
Yes, it sounds like it. As far as I know then both answers should be accepted. All you can do is comment and/or report and hope that someone gets around to fixing it.
It just rejected Tôi sẽ thử viết thư vào thứ bảy này ... huh but that is the answer...
chkadung sez, "I will fix this soon." That was two years ago. Today I consulted a native speaker about using "thử" and they said the other is more proper for this sentence as "thử" not a sure thing. I remarked that two years seemed like when I get invited to dinner at a Vietnamese home, I should show up and hour or so later than the appointed time. They said that is an example of "Vietnam time" or it is "dây thun" or flexible. that is a word everyone should know.
Which is marked wrong--including 'ngày'--in this stupid exercise.
Mind you, if we had a Wikipedia model in place and people here were given the power of editing and adding more correct answers, this could be fixed quickly. This has gone unfixed for two years.
This is an excellent sentence, teaching us the difference between three different 'Thu's.
It's a horrible exercise, because it rejects equally correct answers arbitrarily. It rejects making 'letters' specifically plural, it rejects incorporating 'ngày' in the sentence (required in other constructions here) and it rejects the use of 'cố gắng' which should also be right. Finally, NONE of these errors have been fixed in two years although they have been acknowledged and reported multiple times.