Since Black is in check, it obviously was White's move last, and, because the knight is pinnned by Black's queen, White must have been in check after Black's last move. But in a legal game, White cannot have been in check _before_ that Black move. Lbh arrq gb svaq cynprf sbe gur ebbx naq ovfubc fhpu gung, sbe nal bs Oynpx'f cbffvoyr cerivbhf zbirf, Juvgr jnf va purpx orsber gung zbir. If you still have trouble, wait a day or two and I'll point out another consideration which might help.