Speak your mind – to say what you honestly feel
E.g. Karla was always a very honest person. She was never afraid to speak her mind.
You can always rely on getting a straight answer from John. He will speak his mind even if the truth offends people.
Cross your mind – to briefly think about something; to consider something
E.g. It never crossed my mind to drive to the City. I enjoy train rides, not to mention, it is better for the environment.
Has it ever crossed your mind to put your dirty clothes in the laundry basket? It would make your mother’s job much easier.
Have/Keep an open mind – willing to consider different ideas or opinions, impartial
E.g. My daughter would like to go to college a hundred miles from our house. I wish she stayed closer but I am trying to keep an open mind.
Mary is not religious but would like to keep an open mind about what happens to us after we die.
Have something on your mind - to be preoccupied with a topic, to think a lot about one topic
E.g. Jim has a lot on his mind at the moment, don’t bother him with small stuff.
You are always on my mind. I cannot stop thinking about you.
Keep/bear in mind - not to forget; to remember
E.g. Keep in mind that you cannot bring liquid on the airplane, so pack accordingly.
Bear in mind that you need to call the doctor’s office for the lab results.
Slip your mind - to accidentally forget something
E.g. I am sorry, our appointment completely slipped my mind. Could we set up another time?
I meant to tell you that your mother called, but it completely slipped my mind.
Give a piece of your mind - to speak angrily to somebody about something negative they have done
E.g. I am sure your father will give you a piece of his mind for telling such a lie!
I've had enough of him not doing his homework. I'm going to give him a piece of my mind when he gets home from school.
Out of sight, out of mind - this means that if you do not see someone or something regularly, you will stop thinking about them
E.g. Sarah fell in love with a local boy during their holidays but since they left, they have not kept in touch and she even forgot his name! It is true, out of sight, out of mind.
I meant to read pay that bill but it fell behind the desk, and I forgot about it – out of sight, out of mind!
Mind your own business – to ask someone to stop interfering in or inquiring about someone else’s matter
E.g. Whenever he asks people how much money they make, he gets the same answer: “Mind your own business!”
Her mother always asks Joan about her boyfriends, but she does tell her to mind her own business.