How can I select a NURBS circle?

why I can’t selecte a NURBS circle as a objet? If I want to model a tube, but not using the NURBS tube(I need a long tube)?

space-add-curve-nurbs circle. if you want a nurbs tube, space-add-surface-nurbs tube

You are right. But if I want to do something like skinning with a circle?

mesh modeling. curves are two dimensional equations, not skins. You can bevel and taper them for 3D forms though.
I want to do the samething with circle, but I have no success
In fact, I’m trying to find something I can use for model the sleeves of clothes

space-add-mesh-circle. then extrude in the tubular direction.

good idea, thank you!!