He toiled to start a new business.

This job is really toilsome.

He toiled a lot to complete that project.

He entered the building through the revolving door.

He opened the window to let fresh air into the room.

He decided to study abroad to broaden his horizons.

I caught a cold, so I took one lozenge of medicine.

He struggled to unlock the door.

He struggled to unlock the door.

The protagonist of this novel is a character who unlocks the lock of the key.