if a child is as good as gold, they behave very well.

The children were as good as gold today.

• the roof caves in
• the roof falls in
• the rot sets in
• the rough and tumble of
• the rough and tumble of something
• the rub of the green
• the ... rung on the ladder
• the salt of the earth
• the same old same old
• the same old thing
• the same to you
• the scales fall from eyes.
• the scales fall from someone's eyes.
• the scene is set for
• the scene is set for something
• the school of hard knocks
• the scum of the earth
• the seven year itch
• the shape of things to come
• the sharp end
• the shit hits the fan
• the shit out of
• the shit out of you
• the shoe is on the other foot
• the show must go on.