U.S. vs. Iran: The U.S. must beat Iran to advance. Iran needs a win or a draw against the U.S. to advance, although if Iran draws and Wales wins, Iran could be squeezed out because of goal differential.
Wales vs. England: If England wins or draws against Wales it will advance, but it could also advance if it loses by fewer than four goals. Wales must beat England by four goals or by a smaller margin if the U.S.-Iran game ends in a draw.
Given the stakes, that has been an enormously creditable first half from the U.