what should I do with classmate/ friend who won't study but will complain about failing?

If she won't put anything in, she won't get anything out. However, you can't make her see that; she has to see it for herself. If you feel it's starting to affect you, take some distance from her.

I am trying my best...but it's really hard..I am pretty nice person. .but I am starting to get frustrated, because she/he ask somany questions about system we are doing right now...she barely passed her other class.She complains that's what gets me mad:(

There was someone like this in my nursing program. The best thing you can do is to distance yourself from her: don't sit next to her in class, don't answer her phone calls/texts/emails right way, and when she starts complaining you can develop an urgent need to talk to someone on the other side of the room!

I think you should be honest with her. Next time she says the test was too hard, say, "Why do you think it was too hard? Do you feel like you really prepared for it? How much time are you investing in this?" Make her think. Don't let her get away with thinking she's the victim of an unfair teacher who creates impossible tests. Remind her that she's going to have patients' well-being in her hands one day, and that it's imperative that she takes this seriously. Maybe bluntness will be enough to get her back on track.

How is any of this your problem? If she wants better grades she should study more, simple as that.

And then this person wants join our study group or study with me.

Thank you, guys for your input.

Belive me I am tired of telling her and giving her lecture about how important this school is to me, also her.

And then this person wants join our study group or study with me.

Thank you, guys for your input.

So, she's complaining about something she has the power to change, but won't. On the other hand, so are you. Maybe the two of you have more in common than you'd like to think?

Oh. Well, personally, I would slowly distance myself from her. I don't have much patience for lazy people.

We started school this fall, I became friends with classmate, however everything was doing alright, until she start complaining a lot how she gets bad grades, how the test are

Are you in NP school?