“Once in a blue moon”

“In the loop”

Informed about what is happening.

“In black and white”

Written or printed clearly.

“In short supply”

Not enough available.

“In good faith”

With honest intentions.

“Get in on the act”

To join an activity that others are doing successfully.

“In deep water”

In serious trouble.

“Go hand in hand”

To be closely connected.

“In one piece”

Safe and not damaged.