Matrix Sort
For matrix sort questions, you will see choices of pinyin syllables/words on top. To answer – just drag the syllable to the empty box besides the English meaning which you think it explains the syllable or word. Release it once you see a dotted line box appearing. An example is shown below.
If you want to change the choices after populating them, then you can use the storage area below Sort elements to deposit the choices and move them to the new answer box you desire. Below is a screen grab for illustration.
For incorrect answer, the system will flag those correct matches in the background with green colour. See below picture for info.