Rags to riches:
When someone transforms their life and goes from being poor to being rich.
It's a classic rags to riches story--she went from being homeless to managing a company of 500 people!
A ticket you can use later; a meeting/date moved to another time.
I had tickets for the game, but it rained. I got a raincheck so I can go another day instead.
Raining Cats and Dogs:
It’s really raining cats and dogs out there today!
Rain on your parade:
When somebody ruins your fun or your plans.
He's raining on my parade! I really wanted to enjoy our trip to the museum.
Right the Ship:
Correct problems (especially used in Business English).
When she took over as CEO, she had to right the ship.
Rise and Shine:
Rise and shine honey; time to get up for work!
Rocky (A bit rocky):
Difficult, tough, rough.
I always try to make the best of a rocky situation.
Rome Wasn’t Built in a Day:
Some things take a while to work perfectly.
I just started my company, so of course I’m not rich! Rome wasn’t built in a day!
Run out of Steam:
To lose all of your energy.
I ran out of steam, but I only finished with half of my essay.
Running on empty:
To continue doing something when you have lost almost all your energy.
I'm running on empty right now. I'm going to grab a snack.