难点形成原因：
1.不清楚用法。
2.未注意与它搭配的时间状语。
解决办法：
1.彻底理解过去完成进行时与将来完成时基本用法。
2.注意与它搭配的时间状语。
用法讲解：
一、 过去完成进行时
(一)构成：过去完成进行时是由"had been +现在分词"构成。
She had been suffering from a bad cold when she took the exam. 她在考试之前一直患重感
Had they been expecting the news for some time? 他们期待这个消息有一段时间了吧?
(二)用法:
1. 表示过去某一时间之前一直进行的动作。
过去完成进行时表示动作在过去某一时间之前开始，一直延续到这一过去时间。和过去完成时一样，过去完成进行时也必须以一过去时间为前提。过去完成进行时也是一个相对的时态, 上下文中须有明示或暗示的作为参照的过去的时间。
I had been looking for it for days before I found it. 这东西我找了好多天才找着。
They had only been waiting for the bus a few minutes when it came. 他们只等了几分钟车就来了。
2. 表示反复的动作。
He had been mentioning your name to me. 他过去多次向我提到过你的名字。
3. 过去完成进行时还常用于间接引语中。
The doctor asked what he had been eating. 医生问他吃了什么。
I asked where they had been staying all those days. 我问他们那些天呆在哪儿。
4. 过去完成进行时之后也可接具有"突然"之意的when分句。
I had only been reading a few minutes when he came in. 我刚看了几分钟他就进来了。
She'd only been reviewing her lessons for a short while when her little sister interrupted her.
她温习功课才一会儿，她妹妹就打断她了。
(三)过去完成进行时和过去完成时的比较:
She had cleaned the office, so it was very tidy.
她已经打扫过办公室了，所以很整洁。 (强调结果)
She had been cleaning the office, so we had to wait outside.
她一直在打扫办公室，所以我们不得不在外面等着。 (强调动作一直在进行)
二、将来完成时
(一)构成：will/shall have +过去分词
We hope it will have stopped raining before we set off for the picnic.
我们希望在出发去野餐以前雨就已经停了。
I'll have done all the work by the time you are back this evening.
你们今晚回来的时候我就将做完所有的工作了。
(二)用法：
1. 表示在将来某一时刻将完成或在另一个未来的动作发生之前已经完成的动作。
注意：常与将来完成时连用的时间状语有：
① by (the time / the end of ) + 表示将来时间的短语和句子;
② before (the end of ) + 表示将来时间的词语或句子;
③ when, after等加上表示将来动作的句子等。 例如：
By the year 2050, scientists probably will have discovered a cure for cancer.
到2050年，科学家们可能已经找到治愈癌症的方法了。
By the time you arrive in London, we will have been staying in Europe for two weeks.
等你到达伦敦的时候，我们将已经在欧洲呆了两星期了。
2. 在时间从句和条件从句中，现在完成时可以代替将来完成时，表示将来某时业已完成的动作。例如：
You'll get to like the subject after you have studied it for some time.
在学习这个学科一段时间之后，你就会喜欢它的。
I'll go and see the exhibition as soon as I have finished my work.
我一做完作业就去看展览。
3. 将来完成时还可以表示"可能性"，或"设想"。例如：
It's five o'clock;they will have arrived home by now.
已经五点钟了，他们现在应该已经到家了。
(三)将来完成时与一般将来时的比较：
有具体的时间状语要用一般将来时。如：
Mr Smith will return home on the first Sunday next month. 史密斯先生将于下月的*个星期日回家。
将来完成时的时间状语一般用介词by引入，如：
Mr Smith will have returned home by next month. 到下个月史密斯先生将已回到家了。
