Mr. Ishioka is my best friend.

He accidentally rode his bicycle onto the curb.

They are cultivating flowers of different types.

He is viewing that situation as a serious problem.

He views that situation as a problem.

Neutron stars are known for their density and strong gravity.

He is as stubborn as a head as hard as a stone.

He tripped over the pebble at his feet.

He picked up a stone and threw it.

A neutron is part of an atomic nucleus.