以下段落已变成全对的了.请注意逗号前后的间隔：
Once, a king was looking for a good husband for his daughter. He announced to his people that whoever could answer his question correctly would be allowed to marry with the princess. The question was what made people laugh and cry. Many people answered the question and all were wrong. Just then, a young farmer came up and gave the answer “rain”. When asked to give a reasonable explanation, the farmer replied. "It makes the farmer laugh as his crops grow good . It makes the potter cry as he needs the sun to dry his pots." The king was very satisfied with the answer. So he immediately let his daughter married to the young farmer.
很精彩的故事.如果语法能进一步提高,就更好了.