KICK INTO GEAR
The president kicked into gear his new campaign this week.
The party really kicked into gear after 9pm.
Because John wanted to leave work early, he decided to kick it into gear.
MEANING:
If something kicks into gear, it gets going or started.
"Kick into gear" means "get started."
ETYMOLOGY:
I imagine it is derived from a kind of vehicle like a car or a bike where things are spinning, but the gears aren't engaged, so it isn't moving forward. Then somebody "kicks into gear" the gears, so things start moving forward.
Gear: the toothed wheel that works together with other gears to move a vehicle forward.
REINVENT THE WHEEL
Just use the database as it is and don't try to reinvent the wheel.
He spoke with the fervour of discovery, unaware that he was reinventing the wheel
Everyone thought the supervisor was reinventing the wheel when she adjusted the system her employers use to signin.
MEANING:
If someone reinvents the wheel, they waste their time doing something that has already been done by other people, when they could be doing something more worthwhile.
To redo work unnecessarily when it has already been done satisfactorily;
to rethink an already working system, technique, etc. in a needless attempt to improve it.
Waste a great deal of time or effort in creating something that already exists:
• if it ain't broke, don't fix it
• never change a running system
ETYMOLOGY:
The wheel was already invented thousands of years ago.
It would be useless to spend time trying to 'invent' it again.
THROW SOMEONE UNDER THE BUS
Tom didn't trust his coworkers. He knew that if they got the chance, they would throw him under the bus.
We all knew that David's girlfriend would throw him under the bus the second someone better came along.
John was so angry when his classmates when his classmates threw him under a bus, telling the professor that he had skipped class.
MEANING:
To throw someone under the bus is to get the person in trouble either by placing blame on that person or not standing up for him.
to place or leave (a person or thing) in a bad situation with no assistance, especially in order to protect oneself
ETYMOLOGY:
Imagine he classic imagery of someone about to be hit by a bus… And a friend jumping in the way to save him.
Now imagine someone doing the opposite; ie. Pushing someone into the path of a bus to stop himself getting hit, or just to hurt the other person.