I learned that Indonesian does not differentiate between adjectives and adverbs - if it stands after a noun it's an adjective, if it stands after a verb it's an adverb.
So my question is: Why isn't it "Tini tidak berdiri mantap"?
That was my answer, and was marked wrong, even though it feels to follow a grammatical structure more coherent with the other examples
It is right. I almost wrote this sentence exact, but it sounded too much like my own slang coming through (Australia) so I changed it to steadily just to be more formal.
Idk about the Indonesian part, but if someone isn't standing steady, something is likely physically wrong with them. They could be dizzy, old or have weak legs for example.