"Happiness is a place between too little and too much."
Translation:Hạnh phúc là một nơi giữa quá ít và quá nhiều.
In Vietnamese "hạnh phúc" is both a noun and an adjective. It is more natural if use this way. Though I think there are some nuances in the using of this word between the two languages, "sự hạnh phúc" still can be accepted as a correct answer.
(Personal note: this is a Finnish proverb).
Sự hạnh phúc is in the suggestions, and it's used elsewhere. So when do you use 'sự hạnh phúc and when do you not? That's never been answered.
Here, just from the rules, 'sự hạnh phúc would be indicated, but it's not accepted...that's either an untaught rule or it's yet another arbitrary DL exclusion.
Why is 'một' enforced?
In other exercises, like 'a boyfriend' or 'a relationship' other usages, we are told that 'một' is not necessary as these things are not countable or that it singularity is assumed. So why isn't that true here? How many "places" here can there be?