Naughty Engineers!!!

Four girls took lift in a car full of Engineers. Since no place available, they sat on each boy's lap...

After 5 minutes...
Girl1: Are you an Electronics & Communication Engineer??
Boy1: How do you know??
Girl1: Your tower is communicating with my Unreachable Area.

Girl2: Are you an IT Engineer??
Boy2: How do you know??
Girl2: Your Pen drive is trying to connect with my USB port.

Girl3: Are you a Mechanical Engineer???
Boy3: How do you know??
Girl3: Your Piston is trying to move into my cylinder.

Girl4: Are you a Civil Engineer??
Boy4: How do you know???
Girl4: Your dam has broken and flooded my village....