It's difficult to understand the principles of electrooptics.

I checked the train schedule by looking at the electronic noticeboard at the station.

The children were playing by beating the pellet drum.

He is brushing his lower teeth.

He smiled, showing his lower teeth.

She seemed nervous, biting her lower lip.

She seemed nervous, biting her lower lip.

He was complaining about pain in his armpit.

I plan to spend the afternoon at the library.

The emperor issued an order to the entire army to start the attack.