核心问题
I had thought that we were going to be invited to dinner. 请解释 had thought 的含义。
词典解答
如同 had hoped (meant, expected, planned) 可用来表示“希望”（意图、预料、计划）没有实现一样, had thought 也可以用来表示原来的想法没有实现(即想错了), 因而有时可能暗含有失望的情绪。上面的句子可以译为:
我原以为他们会邀请我们去吃饭的。（实际上他们并没有邀请）
I had thought that he had died twenty years ago. 我原以为他在20年前就去世了。