Dalia...
Idioms are very interesting, but they are often difficult to understand and even more difficult to use properly.
I wrote the following advice (simply my opinion) in a previous italki discussion.
Advice about the Use of Idioms<o:p></o:p>
Idioms, in any language, are difficult to use correctly or in the right situation.
<o:p></o:p>
Idioms are not meant to be interpreted literally.<o:p></o:p>
Instead, they are figurative forms of speech, and it takes many years, even for a native speaker, to know when to use an idiom.<o:p></o:p>
An idiom is an expression used by a particular group of people with a meaning that is only known through common use. For example; "kick the bucket" does not literally mean kicking a bucket with your foot - it means 'dropping dead'.<o:p></o:p>
Do you see how using this idiom incorrectly could cause problems for you? <o:p></o:p>
So, my advice to all English learners is to read them, learn them, but be very careful about using them. In fact, it may be best to avoid using them at least until you have reached an advanced level.<o:p></o:p>