对DIR理解有误。我的其它贴里有解释。对拐点需要加深理解。

来源: LingYuan 于 2020-04-15 03:26:23 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

WENXUECITY.COM does not represent or guarantee the truthfulness, accuracy, or reliability of any of communications posted by other users.