一、在学习英语语法中，过去完成进行时是比较难掌握和理解的一种时态，但是，它在我们英语学习中占着很重要的位置，也是我们学好语法的一个因素，现在，让我们一起来看看过去完成进行时和过去完成时在英语学习应用的主要区别：
过去完成式的形式如下：主语+had+过去分词(done)
1、肯定句：主语+had+过去分词+其他.
2、否定句：主语+had+not+过去分词+其他.
3、一般疑问句：Had+主语+过去分词+其他?
肯定回答：Yes,主语+had
否定回答：No,主语+hadn't
4、特殊疑问句：特殊疑问词或词组+一般疑问句（Had+主语+过去分词+其他）?
5、被动语态：主语+had（hadn't)+been+过去分词+其他

二、一般情况下，在含有过去完成时的句子中，有一前一后两个事情，发生在前的事情用过去完成时，发生在后的事情则用过去时。例如：
1.他到台湾以前，曾学过中文。
He had studied Chinese before he came to Taiwan.
2.他念大学以前，曾前工作过。
He had worked before he decided to go to college.
3.我写这篇有关爱尔兰的小说以前，曾去过爱尔兰。
I had been to Ireland before I wrote this book about Ireland's people.
4.我在上大学以前，已经学过微积分。
I had studied calculus before I got into college.
5. 周一以前，已经下过雪了。
It had already snowed before Monday.

三、如果我们要强调较早发生事件的连续性，我们可以用过去完成进行式。过去完成进行时和过去完成时惟一不同的地方是 had done 的地方一定要用had been doing 。以下是一些过去完成进行式的例子：
1. I had been watching TV before you called me.
2. I had been working hard in a company for many years before I went to college.
3. He had been studying before he went to class.
4. He had been driving all day before he went to sleep.