The set expressions you will hear first in everyday English
It cost an arm and a leg - It was very expensive
How to use this sheet
The line above states one idea twice. On the left sits a fixed expression whose separate words name parts of the body; on the right is the plain wording any dictionary would offer. Nothing in those separate words predicts the meaning, and that gap is what makes an expression idiomatic rather than literal. At this level the sensible goal is recognition rather than production: you need to catch these when a colleague, a film or a neighbour produces one, and to know that reading them word by word will send you somewhere the speaker never intended.
| Expression | Meaning | Typical context |
|---|---|---|
| give someone a hand | help someone, usually with something practical | moving furniture, carrying bags, a task at work |
| keep an eye on | watch something or someone while another person is away | luggage, children, food on the stove |
| make up your mind | finally decide between two or more options | choosing in a shop, ordering in a restaurant |
| a piece of cake | something that turned out to be very easy | after a test, an interview, a small repair |
| cost an arm and a leg | be far more expensive than expected | rent, flights, dental work |
| once in a blue moon | very rarely, hardly ever | talking about habits and routines |
| under the weather | slightly unwell, not seriously ill | explaining an absence from work or class |
| break the ice | say or do something so that strangers start talking | first meetings, parties, a new class |
| call it a day | stop working and finish for now | the end of a shift or a study session |
| get the hang of it | learn to do something after some practice | new software, a new job, driving |
| on the same page | agreeing about what is happening or planned | meetings, team projects, family decisions |
| in the long run | over a long future period, not immediately | weighing up a decision |
In use
Could you give me a hand with these boxes before the lift closes? We only eat out once in a blue moon, so tonight feels like a treat. I'm still getting the hang of the new booking system, so be patient with me.
Watch out
We are all in the same page about the new schedule.
The incorrect sentence changes one two-letter preposition inside the eleventh expression, and that single change is enough to break it. Learners reach for the preposition of containment, because in many languages agreement is imagined as being inside a shared space. The English picture is flatter: several people are looking down at one sheet of paper, so the preposition of contact with a surface is the one that survives. The lesson goes well beyond that row. Every expression in the first column is frozen. Swap a preposition, make a singular noun plural, or replace a verb with a close synonym, and a listener hears a mistake rather than a variant.