Popular Idioms & Expressions | American English 🇺🇸 Learn these useful idioms and expressions to help you better understand American English. This will help you build your vocabulary while improving your overall fluency. I'm confident this lesson will be a piece of cake. Here are the expressions from the lesson. 1) piece of cake 2) to run late / to run behind 3) to get the hang of (something) 4) all set / all good 5) to sound like a broken record 6) to pitch in 7) to blow off some steam 8) it's