They can switch on and off a billion times a second.

The young student had gone in before them and switched on the light.

I switched on the reading light at the head of my bed.

She went to the door and switched on the light.

He put out a hand and switched on a light.

She switched on the light and got out of bed.

She put out her hand and switched on the light.

A very old couple came in and switched on the television.

He switched on the light, sat up and looked around.

He opened his front door and switched on the light.