@dsibley,

You can click on "on-click answers" in the right column before taking a quiz.

--Echo

@dsibley,

If you enable "on-click answers" you can click on different answers to find out which one is the correct one. The system locks down your answer so you can't change it, but the green and red flashes let you find out the correct answer through experimentation if you need it. A pretty good approach imo.

@opavlikova,

We've been struggling with how best to answer your question, since it deserves a better answer than just saying that 坐下来 is right and that this is just one of those things to remember for the HSK. When we pushed Echo on it the answer we got back was that the difference is largely "about the tone and emotion" and that even though there is nothing technically wrong with 坐下去 people just don't use it often if at all.

When we surveyed them on all the tone/emotion front, our Chinese staff reached the conclusion that 坐下去 it puts an emphasis on the thing which is sat upon rather than the person who does the sitting. It also shows up in the continuous aspect, as with 他一直坐下去. In contrast, 坐下来 does exactly what you'd expect: it focuses on the person, the movement and the action.

So that was a really good question. Interestingly, a Google search confirms the relative frequency of these terms in the wild. 坐下来 seems to be about 10x as popular as 坐下去. Strange.