to quit on

to stop working/functioning especially at a time of trouble: Please don’t quit on me now, just when things are getting difficult. 

Typical! I’ve got a deadline in 20 minutes and my computer’s quit on me.

to rake in

to earn a lot of money: Bob set up his own business 3 years ago. It was difficult at first, but I hear he’s raking it in now. 

to ramp (something) up

to increase, boost: This year we plan to ramp up sales, so we’re employing 3 more sales staff.

to read up on

to research: I’d like you to read up on entering the Chinese market.

to ride (something) out

to get through a difficult time: If we can just ride out this recession, we should be well positioned to take the lead on the competition.

to rip (somebody) off

to charge an excessive amount of money or obtain money unfairly: Look at this umbrella. I bought it half an hour ago from a guy at the train station and it’s already broken. He ripped me off!

Similarly the compound noun “rip-off” means something that was not worth what you paid for it.

to roll out

to launch: We’re planning a big party when we roll out the new product.

to rule (something) out

to exclude a possibility: The merger is on hold for the moment, but it may happen in the future. We’re not ruling it out entirely.

to run into

to meet somebody without planning to: I ran into Fiona in Starbucks the other day. She’s working at BigCo now.

to run through

to practise: Can I run through my presentation with you this evening. I’d really value your opinion.

to run up

to spend money on credit: Anna has run up a huge debt on her company credit card.