英语present progressive and present perfect progressive what i

英语present progressive and present perfect progressive what is different
现在进行时 和过去现在进行时 的不同 I need example

The present perfect progressive says the action started happening before the time you say the sentence and continues up to the time of your saying it.Maybe the action stops just before you say the sentence and maybe the action continues as you say the sentence,or even continues after you say the sentence,but the main idea is that it starts before you say the sentence.Again,suppose it is 6 o'clock.
He has been watching TV.(Now,as I speak,at 6 o'clock,I see that he has been watching TV from 3 o'clock until now.- or from 1 o'clock until now - or from 2:30 until now.-- The amount of time is not specified.)
He has been watching TV for two hours.( Now,as I speak,at 6 o'clock,I see that he has been watching TV from 4 o'clock until now.-- The amount of time is specified in this case.)
It has been raining.(Now,as I speak,at 6 o'clock,I see that it has been raining from 3 o'clock until now.- or from 1 o'clock until now - or from 2:30 until now.-- The amount of time is not specified.)
It has been raining for a half hour.( Now,as I speak,at 6 o'clock,I see that it has been raining from 5:30 until now.-- The amount of time is specified in this case.)
What have you been talking about?(Now,as I ask,at 6 o'clock,I ask the topic(s) of conversation during previous time up to the moment I ask.)
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Another way the present perfect progressive can work,if no amount of time is specified,is that the action occurred in the past and continued for some time and then stopped,but there is evidence at the time of speaking that the action did occur.
It has been raining,but it is not raining now.(I know because I can see now that the streets are wet.)
The children have been playing ball in the family room,but they are not playing ball there now.(I know because the ball is there,and it should be in the garage.I know because there is a mark on the wall where the ball probably hit the wall.I know because I can see the lamp overturned and broken on the floor.)
This last pattern often occurs with must to show that the speaker has reached a logical conclusion from the evidence before him.
It must have been raining,because the streets are wet.
The children must have been playing ball in the family room,because the lamp is broken.