extrusion surface from sketch

[rtas]

Good morning.
to model surfaces I have always adopted the technique of drawing the 3 sketches of the three views (frontal, side and vertical); and then extrude the single edges of the sketches. Suddenly, though, I can't pick a single edge anymore, but I can't choose the whole sketch. !
Please help me! :

 

[goccia]

Because you're out of the sketch form.
use command line 3d.