I'm still undecided.
I don't know yet.
まだ調べてないんだ。
It is still difficult to decide that.
I don't know if I still have it.
That is something I still do not know about.
I haven't decided about that yet.
I haven't decided about that yet.
I still don't understand how to do that.
I don't know for certain yet.
I don't know exactly yet.