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

Ryusuke is my best friend.

The muddy stream hit the town.

A lot of driftwood was washed up on the beach.

In this experiment, we will observe the behavior of α particles.

The liquidity of this company is very high.

He drifted all night at sea.

His boat was drifting at sea.

The luggage got piled up at the airport.

His work is piling up.