Can't select all vertices of circle I'm practicing blender 3d v2.79
By the last 3 weeks when get inside the edit mode i can't select the whole circle of vertices by hitting Ctrl+alt +left click

In the beginning i thought that my laptop keyboard is the problem and i connected an external keyboard and did the same and even my laptop did the same what is the problem

What is the reason, is my short cut wrong 
Give me a suggestion
You have the wrong shortcut, it just Alt+Left click. It will select all the vertice lying along its path.

All the best!