present perfect contiunous tense vs past continuous tense

I started to read some grammar book , but find difficulty to distinguish between " present perfect contiunous tense " and " past continuous tense " . It seems that both means an action started in the past and will be continued at the the time of speaking .

For example :
I have been reading for two hours .
I was reading this morning .
I was reading since two hours ago .

Which is better ? Is there any difference in meaning between these three sentence .

Thank you for your help in advance .

Quote:

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Originally Posted by dkyeung

I started to read some grammar book , but find difficulty to distinguish between " present perfect contiunous tense " and " past continuous tense " . It seems that both means an action started in the past and will be continued at the the time of speaking .

For example :
I have been reading for two hours .
I was reading this morning .
I was reading since two hours ago .

Which is better ? Is there any difference in meaning between these three sentence .

Thank you for your help in advance .

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I have been reading for two hours . I started reading two hours ago, I am still reading or I have just stopped.
I was reading this morning . At some point this morning I was reading, it's finished I am not reading now.
I was reading since two hours ago . This is grammatically incorrect. You could say: "I have been reading since two o'clock." We use "since" with a specific time reference.

Quote:

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Originally Posted by bhaisahab

I have been reading for two hours . I started reading two hours ago, I am still reading or I have just stopped.
I was reading this morning . At some point this morning I was reading, it's finished I am not reading now.
I was reading since two hours ago . This is grammatically incorrect. You could say: "I have been reading since two o'clock." We use "since" with a specific time reference.

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Thanks for your comment . My English is poor and I want to clarify more . Is it possible to express the meaning of the first sentence ( I started reading two hours ago , I am still reading ) in past continuous tense . If it can , would you please show me an example . Thanks .

Quote:

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Originally Posted by dkyeung

Thanks for your comment . My English is poor and I want to clarify more . Is it possible to express the meaning of the first sentence ( I started reading two hours ago , I am still reading ) in past continuous tense . If it can , would you please show me an example . Thanks .

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Yes,
I have been reading for two hours.= I started reading two hours ago, I am still reading or I have just stopped.

My sentence in blue gives you the meaning of your original sentence, sorry if I didn't make that clear.