ought to have done和should have done都是虚拟语气,只是前者

只能用在单个的句子当中，而后者可用于带条件状语从句的主句当中，对吗？

should have done 可以换成 ought to have done嘛？ ought to 请解释ought to have gone along 为什么to 后面有have呢，不明白。谢谢 Mary ought to have been here by now. Iwonder what's happened to here.是什么意思 ought to do和have to do以及should do有什么区别？ 关于句子I ought first to have asked your consent.的疑问 I ought to have insisted on __a thorough rest before you left for New York. l have already bought twenty bottle of beer ,they ought to be enough for us two. You uoght to have given them some advice?So I did.为什么不用So I ought ought to的用法