#1 - Hit the books
This idiom simply means to study, especially with particular intensity. It is used as a verb – hit the books.
“They go to the beach when they should be hitting the books and then they wonder why they get bad grades”
#2 - Hit the sack
“(to) hit the sack” generally means to go to bed. You can also say “hit the hay” which has the same meaning.
“…A soldier gets tired feet and is eager to hit the sack.”
“Time to hit the hay”
#3 - Twist someone’s arm
The idiom "twist someone’s arm" generally means to persuade someone to do something. If someone twisted your arm, it means that someone has done a great job of convincing you to do something you might not have wanted to do.
“They had to twist his arm, but they got him to join the project”.
#4 - Up in the air
“(to be) up in the air” is and English Idiom meaning that something has not been resolved, finished or answered yet. It usually refers to a plan or a decision that has not been decided or being uncertain.
“I think I can do it quickly, but the exact schedule is still up in the air.”
#5 - Lose touch
The idiom “(to) lose touch” means to cease to be familiar with someone or something (e.g. some certain skills or talent). This also refers to the lost in the ability to communicate or have contact with others. To make it simple, if you lose your touch, you lose your ability or skills you once had when working with things/situations, or dealing/communicating with people.
“Suddenly, friends found me again that I had lost touch with years ago”
“It looks like you’ve lost your touch with the girls in class”
#6 - Sit tight
The saying “(to) sit tight” means to wait patiently or to remain quiet or relatively motionless. If somebody tells you to sit tight, they would like you to wait and take no action until they say otherwise.
“I'll be back in a few minutes, so sit tight while I go find her”
#7 - Pull someone’s leg
The saying “pull someone's leg" means to tease someone, to lead someone on or to goad someone into overreacting. The term usually implies teasing or goading by jokingly lying. A brief translation of this saying could be to “fool or trick someone”.
“I hadn't pulled Ms Jane’s leg for any of that stuff, she had just handed it to me on a platter, and that wasn't my fault”
#8 - Face the music
The idiom “(to) face the music” means to accept or confront the unpleasant consequences of one's actions. It is used as a verb – face the music.
“He failed the exam as he was so lazy. So he’s going to have to face the music”
#9 - On the ball
The saying “(to be) on the ball” is typically used to reference someone that is alert, active, or attentive. A brief translation of this idiom would be “on top of things”.
If you say someone is “on the ball”, you mean that he or she understands the situation well.
“If I had been more on the ball I would have asked when he called me”
#10 - Under the weather
The saying “(to be)under the weather” is generally used to reference someone that is somewhat ill or gloomy. So “feeling a bit under the weather” simply means feeling slightly ill.
“I’m sorry, I feel a bit under the weather, I think I cannot join the party tonight”