Answer:
Hello! Idioms are commonly used expressions whose meanings are changed and generally figurative, but they can be understood because of their popular use. We use idioms because they enable us to express ourselves in a distinctive and innovative way. In addition to helping us express our ideas and opinions, idioms promote cultural and historical information! Here are your answers:
- I'm in love with you. This is NOT an idiom: it's a literal expression of someone's feelings for another person.
- I'm head over heels for you. Would you literally be tumbling head over heels because of another person? Probably not. This is an idiom that means you're madly in love with someone.
- Focus on what's important. This is NOT an idiom: it's a literal, direct expression that tells you exactly what to do.
- Cut to the chase. This is an idiom that's prompting you to come to the point and only deal with the important part(s) of a subject.
- She frustrates me. This is NOT an idiom: it's a literal expression of the way a person's emotions are impacted by someone else.
- She drives me up the wall. Is someone literally pushing you up a wall? Not likely! This is an idiom that means someone is making you feel irritated and angry.
Hope this helps! Have a great day.
(P.S. Idioms are indeed deeply affected by culture! One interesting Spanish idiom is "dar calabazas a alguien" - to give pumpkins to someone, which means you're rejecting someone. This is a very unique way of expressing rejection and wouldn't be understood in all cultures!)