The erection of the new building has begun.

We made a plan to erect a new school.

He is living in exile for political reasons.

He had to wander from his hometown because of the war.

In this river, the counter current is very strong, so caution is necessary.

The river water is flowing back.

He steered the boat down the rapids.

Ryunosuke is my best friend.

Ryuichi is my best friend.

The source of this river is at the top of the mountain.