Complex sentence: This is of course a bad move, because it leads to losing not only the queen, but even a rook, but since the loss of the queen was pushed over the horizon of search, it is not discovered and evaluated by the search.
Split into simpler sentences: This is of course a bad move, because it leads to losing not only the queen, but also a rook. However, since the loss of the queen was pushed over the horizon of search, it is not discovered and evaluated by the search.