【英语语法】请帮我分析一下这个句子的结构!新概念三 Lesson49 The Ideal Servant 里的句子：The guests had,of course,realized this from the moment Bessie opened the door for them and,long before the final catastrophe,had had a difficult time trying to conceal their amusement.那两个连在一起的had，是什么时态？

the guests（主语） had,of course（插入语）,realized （谓语）this（宾语） from the moment Bessie opened the door for them（时间状语）,and（连词） long before the final catastrophe（时间状语）,had had （谓语）a difficult time（宾语） trying to conceal their asumement（主语补足语）.
当然，在Bessie开门的时候，客人们就意识到了这一点，而且离最后的灾难很久以前，他们就已经为试着掩饰他们的asumement而痛苦一段时间。
had had a difficult time trying to conceal their amusement
这里是过去完成时态，第一个had 后面要就过去分词，所有第二个have 就变成了had，所有就有两个had ， 这里had a difficult time 的原形是have a difficult time ，是指很难怎么样

the guests（主语） had,of course（插入语）,realized （谓语）this（宾语） from the moment Bessie opened the door for them（时间状语）,and（连词） long before the final catastrophe（时间状语）,had had （谓语）a difficult time（宾语） trying to conceal their asumement（主语补足语）.
当然,在Bessie开门的时候,客人们就意识到了这一点,而且离最后的灾难很久以前,他们就已经为试着掩饰他们的asumement而痛苦一段时间.
had had a difficult time trying to conceal their amusement
这里是过去完成时态,第一个had 后面要就过去分词,所有第二个have 就变成了had,所有就有两个had ,这里had a difficult time 的原形是have a difficult time ,是指很难怎么样