English Idioms and Expressions 

Idioms: Intelligence, Smartness and Comprehension-1
from:  'be on the ball'  to: 'common ground'

• be on the ball
  • If you are on the ball, you are aware of what is happening and are able to deal with things quickly and intelligently.
    "We need someone who is really on the ball to head the fund-raising campaign."
    
    
• beat one's brains out
  • If someone beats their brains out, they try very hard to understand something or solve a problem.
    "My grandmother beats her brains out every evening trying to do the crossword puzzle in the newspaper."
    
    
• it beats me!
  • This expression is used to express surprise at something that you find difficult to understand.
    "It beats me how he can live in that horrible apartment!"
    
    
• it's beyond me
  • To say 'it's beyond me' means that it is impossible for you to understand.
    "It's beyond me why Mary wants to marry John."
    
    
• blind you with science
  • If someone tries to blind you with science, they confuse you with their knowledge by using difficult or technical words.
    "When you ask Tim for a simple explanation, he blinds you with science."
    
    
• I wasn't born yesterday
  • This expression is used to indicate that you are not as foolish or as easily deceived as some people seem to think.
    "Stop inventing silly excuses. I wasn't born yesterday you know!"
    
    
• (the) brains behind something
  • Someone who is the brains behind a project or action is the person thought to have planned and organised everything.
    "The police have arrested a man believed to be the brains behind the bank robbery."
    
    
• can't make head or tail of (something)
  • If you can't make head or tail of something, you can't understand it at all.
    "Amy's message was so confusing. I couldn't make head or tail of it!"
    
    
• put on your thinking cap
  • If you tell someone to put their thinking cap on, you ask them to find an idea or solve a problem by thinking about it.
    "Now here's this week's quiz; it's time to put your thinking caps on!"
    
    
• chinese arithmetic
  • If something is very complicated or difficult to understand, it is said to be like Chinese arithmetic.
    "When he tried to explain the rules of the game to me, it was like Chinese arithmetic!"
    
    
• not have a clue
  • If you don't have a clue about something, you don't know anything about it.
    "My wife's grandmother's maiden name? I don't have a clue!"
    
    
• collect one's thoughts
  • If you collect your thoughts, you try to think calmly and clearly in order to prepare yourself mentally for something.
    "Anne stopped to collect her thoughts before calling back the unsatisfied customer."
    
    
• come to grips with
  • If you come to grips with a problem or situation, you start to understand or deal with it properly.
    "After the initial shock, the patient began to come to grips with his disability."
    
    
• come to your senses
  • If you come to your senses you start to think clearly and behave sensibly.
    "She finally came to her senses and realized that public transport was faster than driving in the city."
    
    
• common ground
  • This expression refers to an area of shared beliefs, interests or mutual understanding between people or groups who often have disagreements.
    "Any common ground among the Mediterranean countries will contribute to future unity."