The first one isn't grammatically very good translation, buuuut .... 1. She had been studying, but, nowadays she isn't a student. 2. She has been a student when she's told it.

She told me that she was a student. - In the Past. It means that she was a student, but not anymore. She told me that she is a student. - In the Present. She is a student NOW.

Hello, Chris. I appreciate your useful comment. It helps me a lot :-)

The first sentence is an example of reported speech. You are relating what she told you previously. When she told you she was a student, she would have said "I am a student". When you tell this to someone else, you change the verb "is" into the past tense. She told me she was a student. It doesn't mean that she is no longer a student. The second sentence is also an example of reported speech. In English you can keep the verb "is" in the present tense, even though you are reporting what someone said. You can do this if the fact you were told is still true when you are retelling it. She was a student when she first told you and she is still a student when you are retelling the conversation. So what is the difference - the first sentence follows the grammar rules for reported speech more strictly; the second sentence is still grammatically correct, but is more informal and can suggest that the reported fact - Her telling you that she was a student - is more recent in time.