It’s correct. This course is still in beta, so it sometimes doesn’t accept correct variants because the authors didn’t think about them. Next time you get this question, please report this error to the course creators by clicking on 'My answer should be accepted'.
"I am going there sometimes" doesn't really work because of the "sometimes", it changes the sentence. In this case, you wouldn't use the present tense "going", you'd just say "I go there sometimes" (or "I sometimes go there" or "sometimes I go there"). Does that make sense?
- туда = there, to that place,
- куда? = where?, to what place?
Aside from being an interrogative pronoun, куда can also be used to connect clauses in a complex sentence:
- Она знает, куда я хожу. She knows where I go.
Well, yes. Or it can be used in a question that's not a question about place (e.g. Заче́м она́ туда́ ходи́ла? 'Why did she go there?').
It doesn't give me the option to reply to your last post and I can't seem to find anyway to directly message you so I'll respond here. I understood там to mean "there" as in -"где мяч?" -"там" pointing to someplace.
The example I was referring to was "зачем она туда ходила?". I guess they just mean different kinds of "there" then?
Right, there're different kinds of 'there':
- Why did she go there (=to that place)?
- Where is the ball? It's there (=in that place).