A Grain of Sand Here is a story. A participant in the long-distance race got his shoes filled with sand when he was crossing a beach. He had to stop to get the sand out hastily before he resumed running. Unfortunately a grain of sand remained rubbing the sole and became increasingly telling so that each step meant a twinge of pain. Reluctant to halt and get rid of the sand， he continued to run in spite of the pain until he could stand no more. He dropped out of the contest just a few yards from the finishing line. As he managed to get out of the shoe painfully， he was surprised to find the cause of his lasting torment was only a grain of sand. It seems that the greatest obstacle on one’s way forward may not be a high mountain or a deep valley but a grain of sand that is hardly visible. To avoid blame on a minor fault one may tell a lie. That adds a burden to a heavy heart and weighs it down. In the days to come he will have to fabricate one falsehood after another to cover the lie he told and the fault he committed. Thus he will never be able to free himself from lingering anxiety, worry and regret, to the ignorance that all his sufferings originate in only a grain of sand —the first lie he told. ↑Question：What does ‘to the ignorance that ’of the third to the last line mean in this article？