"cái kính màu đen" should also be accepted.
That s a good idea to discuss that in vietnamese
You forgot the /s tag. ;)
Why is "một" needed?
Dịch lạ vậy?
mot is one! or singular! why is it needed?
I'm just guessing, but in some languages, including English, glasses are plural; but in some languages what you put on your nose to see better is one thing, and grammatically singular.