Learning english

1. ‘The best of both worlds" - means you can enjoy two different opportunities at the same time.
"By working part-time and looking after her kids two days a week she managed to get the best of both worlds."

2. ‘Speak of the devil" - this means that the person you"re just talking about actually appears at that moment.
"Hi Tom, speak of the devil, I was just telling Sara about your new car."

3. ‘See eye to eye" - this means agreeing with someone.
"They finally saw eye to eye on the business deal."

4. ‘Once in a blue moon" - an event that happens infrequently.
"I only go to the cinema once in a blue moon."

5. ‘When pigs fly" - something that will never happen.
"When pigs fly she"ll tidy up her room."