===== Idioms =====
**What it is:** Fixed expressions with meanings different from the literal words.  
**What it’s for:** Understand movies, jokes, and natural speech.  
**Example:** “It’s raining cats and dogs.” = raining very heavily.

===== How to learn idioms safely =====
  * Learn only high-frequency idioms.
  * Always learn with context + one example sentence.
  * Don’t force idioms in formal writing.

===== Starter idioms =====
  * **break the ice:** start a friendly conversation
  * **piece of cake:** very easy
  * **once in a blue moon:** very rarely

===== Hard words (Glossary) =====
  * *idiom* /ˈɪdiəm/: thành ngữ
  * *literal* /ˈlɪtərəl/: nghĩa đen
  * *context* /ˈkɒntekst/: ngữ cảnh
  * *frequency* /ˈfriːkwənsi/: tần suất