这句话对,除了打字错误yong---->young
he said he could swim when he was very young我想问一下 为什么这里的 was 不往后退一个时态直接变间接不应该变时态吗不必，为什么若原句为一般现在时：he says :" I could swim when i was very yong"，改成间接引语，还是he says he could swim when he was very young，对吗？还是有点不明白