We have built a close relationship.

Their closeness is the result of years of collaboration.

He struggled to get through the dense thicket.

He is good at stealth operations.

He left the room stealthily.

This dessert is full of syrup-covered anko and fruit.

They were secretly scheming a new project.

They were plotting a secret scheme.

The sky was covered with dense clouds, and it started to rain.

This machine is made with very detailed parts.